EXAM 2

What are the major causes of deterioration of vegetables after harvest?

The major causes of deterioration of vegetables after harvest include:

1. Water Loss (Transpiration)

   • Vegetables have high water content.

   • Water loss reduces weight (thus revenue), appearance (wilting, shriveling), texture, and nutritional quality.

   • Factors increasing water loss: high surface area to volume ratio (leaves, asparagus), damaged skin or dermal tissue, presence of leaves or tops on some vegetables like carrots.

2. Respiration

   • Cellular process consuming oxygen and carbohydrates; releasing CO2, water, and energy.

   • Higher respiration rates accelerate quality deterioration and shorten storage life.

   • Influenced by temperature (higher temp increases respiration), oxygen level (more oxygen increases respiration), carbon dioxide (higher CO2 reduces respiration), and humidity (higher humidity tends to reduce respiration).

3. Wounding and Biochemical Responses

   • Physical injury during harvest triggers synthesis of phenolics and lignin for healing.

   • Phenolic accumulation can cause bitterness, off-colors, and poor texture.

   • Wounding increases water loss and susceptibility to pathogens.

4. Ethylene Exposure

   • Plant hormone that promotes ripening, senescence, and tissue changes.

   • Produced by climacteric fruits (apples, tomatoes, peaches) and external sources (smoke, exhaust).

   • Causes disorders such as yellowing of broccoli, toughening of asparagus, sprouting in potatoes, and off-flavors.

5. Temperature and Humidity Conditions

   • Higher temperatures accelerate respiration, water loss, and ethylene effects.

   • Improper humidity can increase water loss or disease.

   • Chilling injury can damage warm-season crops stored too cold.

6. Pathogen Infection

   • Injuries and warm, moist conditions can promote decay through pathogen entry and growth.

What is respiration and why is it important for post harvest vegetable management?

Respiration is the metabolic process by which plant tissues consume oxygen (O₂) and carbohydrates to produce carbon dioxide (CO₂), water, and energy. The general chemical reaction can be summarized as:

O₂ + carbohydrates → CO₂ + water + energy

Why Respiration is Important in Post-Harvest Vegetable Management:

• Indicator of Quality and Storability:
  The rate of respiration correlates with how quickly vegetable quality deteriorates after harvest. Higher respiration rates mean faster depletion of the vegetable's stored carbohydrates and greater loss of quality.

• Influences Shelf Life:
  High respiration speeds up metabolic activities that lead to spoilage, nutrient loss (e.g., vitamin C oxidation), texture changes, and overall reduced shelf life.

• Environmental Influences:
  Respiration rate is affected by factors such as:

  • Temperature: Higher temperatures increase respiration, accelerating deterioration.

  • Oxygen Levels: Higher oxygen increases respiration; lowering oxygen (modified atmosphere) slows respiration.

  • Carbon Dioxide Levels: Elevated CO₂ tends to reduce respiration.

  • Humidity: Higher humidity reduces water loss and can slow respiration.

• Management Goal:
  To extend shelf life and maintain quality, the goal is to reduce respiration rate by:

  • Cooling produce quickly and storing it at low but non-damaging temperatures.

  • Using modified atmosphere storage (low O₂ and high CO₂).

  • Maintaining high humidity.

By controlling respiration, growers and handlers can slow down the natural aging and deterioration processes in vegetables after harvest.

What factors increase the rate of respiration of vegetables?

Factors that increase the rate of respiration in vegetables include:

1. Higher Temperature

   • Respiration rates rise significantly with increasing temperature, speeding up metabolic processes and quality loss.

2. Higher Oxygen Concentration

   • More oxygen available promotes faster respiration because oxygen is a reactant in the process.

3. Lower Carbon Dioxide Concentration

   • Reduced CO₂ means less inhibition of respiration; elevated CO₂ tends to slow respiration.

4. Lower Humidity (Indirectly)

   • While humidity mostly affects water loss, lower humidity can stress tissues and may influence respiration rates.

5. Physiological Factors:

   • Crop type: Some vegetables naturally respire faster (e.g., asparagus, sweet corn, peas) than others (e.g., onions, watermelon).

   • Crop maturity stage: More mature or ripe tissues may respire faster.

   • Physical damage or wounding can also increase respiration as the plant responds to injury.

Summary:
To manage post-harvest respiration and slow deterioration, keep temperatures low, reduce oxygen levels in storage atmospheres (modified atmosphere), increase CO₂ where appropriate, and minimize damage and stress to the produce.

Give examples of vegetables with very high and low rates of respiration.

Vegetables with Very High Respiration Rates

• Asparagus (notoriously high respiration)

• Sweet Corn (especially older varieties)

• Peas

These vegetables tend to deteriorate quickly and often require rapid cooling and careful storage.

Vegetables with Very Low Respiration Rates

• Onions

• Watermelon (surprisingly low for a fruit/vegetable)

• Potatoes (though they have special storage considerations)

These vegetables have longer storage life and are less sensitive to rapid quality loss through respiration.

Managing respiration rates according to these differences is key to effective post-harvest handling.

Why are they sometimes not removed in grocery stores

In grocery stores, some non-edible or water-loss-prone parts like carrot leaves (tops) are sometimes not removed because:

• Visual Freshness Indicator:
  Leaves or tops on carrots signal that the vegetable is very fresh, which appeals to consumers and can encourage purchases.

• Aesthetic Appeal:
  The presence of leaves can make the produce look more natural, vibrant, and attractive on display.

Why is it recommended that the tops of carrots be removed for optimal storage?

It is recommended to remove the tops (leaves) of carrots for optimal storage because:

• Carrot tops lose water quickly, as they have a high surface area and are designed to transpire.

• Leaving the tops on causes the carrot root to lose moisture faster, resulting in quicker wilting and quality deterioration.

• This leads to weight loss, reducing marketable yield and revenue.

• Removing the tops minimizes water loss from the carrot, helping maintain freshness and extending storage life.

• Additionally, it reduces the risk of pathogen entry through damaged or decaying tops.

What is ethylene, and what are some disorders associated with exposure of vegetables in storage to
ethylene?

What is Ethylene?

• Ethylene is a plant hormone that acts at very low concentrations.

• It regulates many physiological processes such as ripening, senescence (aging), abscission (shedding), germination, root formation, and respiration.

• Ethylene is produced intrinsically by ripening climacteric fruits (like apples, peaches, tomatoes) and can also come from external sources like cigarette smoke, vehicle exhaust, or fires.

---

Disorders Associated with Ethylene Exposure in Vegetables:

• Leaf Disorders: e.g., russet spotting on lettuce.

• Off-Flavors: accumulation of compounds such as isopumerins in carrots causing unpleasant tastes.

• Tissue Toughening: e.g., asparagus becomes tougher.

• Loss of Color (Chlorosis): especially in broccoli and cabbage, causing yellowing of normally green parts.

• Fruit Softening: accelerated ripening and softening in fruits.

• Potato Sprouting: ethylene can induce sprouting in stored potatoes.

---

Management Notes:

• Sensitive vegetables are often stored separately from ethylene-producing climacteric fruits.

• Some commercial systems use ethylene inhibitors (e.g., MCP) to prevent ethylene’s negative effects on stored vegetables.

What are climacteric fruit? Why is it important to know which fruit/vegetables are climacteric?

What Are Climacteric Fruits?

• Climacteric fruits are fruits that produce a significant increase in ethylene gas and show a spike in respiration rate as they ripen.

• Examples include apples, peaches, pears, tomatoes, and muskmelons.

• These fruits continue to ripen after harvest, largely regulated by ethylene production.

---

Why is it Important to Know Which Fruits/Vegetables Are Climacteric?

• Ethylene Production: Climacteric fruits release ethylene, which can cause or accelerate ripening and spoilage in other produce.

• Storage Considerations: Storing climacteric fruits with ethylene-sensitive vegetables can cause quality loss such as yellowing, toughening, off-flavors, or premature decay in vegetables.

• Post-Harvest Management: Knowing which fruits are climacteric helps growers and handlers:

  • Separate storage to avoid ethylene exposure to sensitive produce.

  • Manage ripening processes intentionally (e.g., using ethylene inhibitors).

  • Optimize storage conditions and extend shelf life for both fruits and vegetables.

Proper separation and handling reduce economic losses and maintain produce quality during storage and transport.

What are the advantages of cooling vegetables quickly following harvest?

The advantages of cooling vegetables quickly after harvest include:

• Reduces Respiration Rate: Rapid cooling slows down metabolic activity, preserving carbohydrates and extending shelf life.

• Minimizes Water Loss: Cooler temperatures reduce transpiration, helping maintain weight, texture, and appearance.

• Slows Ethylene Effects: Lower temperatures decrease the rate at which ethylene-driven ripening and senescence processes occur.

• Reduces Wound Responses: Cooling slows wound-induced biochemical reactions (e.g., phenolic production) that can cause bitterness and discoloration.

• Limits Pathogen Growth: Cooler conditions inhibit many spoilage organisms and reduce decay incidence.

• Maintains Nutritional Quality: Slower respiration and biochemical activity help preserve vitamins (e.g., vitamin C) and other nutrients.

What vegetables are most sensitive to chilling injury?

Vegetables most sensitive to chilling injury are typically warm-season crops that have evolved in warmer climates and do not tolerate cold storage temperatures well. Examples include:

• Tomatoes

• Cucumbers

• Peppers

• Eggplants

• Squash (some types, particularly summer squash)

These vegetables generally should be stored around 10 °C (≈50 °F) to avoid chilling injury. Storing them at temperatures too close to freezing or below their chilling threshold can cause physiological damage, such as:

• Pitting or surface lesions

• Uneven ripening or poor flavor development

• Increased susceptibility to decay

• Tissue breakdown

In contrast, cool-season vegetables (like lettuce, broccoli, carrots) are less sensitive and can be stored at temperatures closer to freezing without injury.

If you were a diversified vegetable producer and had four storage rooms that could be set at any
temperature or relative humidity, what would you choose? Which vegetables would you put in which

storage room?

If you had four storage rooms with flexible temperature and relative humidity (RH) control as a diversified vegetable producer, a practical storage setup could be:

---

Storage Room 1: Cool-Season Crops (Chilling-Insensitive)

• Temperature: ~0–2 °C (33–36 °F)

• Relative Humidity: High (~90–95%)

• Vegetables Stored:

  • Leafy greens (lettuce, spinach, chard)

  • Broccoli, cabbage

  • Carrots, beets

  • Onions and garlic (slightly lower RH, but can be accommodated)

  • Potatoes (monitor temp to avoid too cold)

---

Storage Room 2: Warm-Season Crops (Chilling-Sensitive)

• Temperature: ~10 °C (50 °F)

• Relative Humidity: High (~90–95%)

• Vegetables Stored:

  • Tomatoes

  • Peppers

  • Cucumbers

  • Eggplants

  • Summer squash

---

Storage Room 3: Ethylene-Producing Fruits

• Temperature: Optimized per crop (often similar to warm-season crops)

• Relative Humidity: High (~90–95%)

• Produce Stored:

  • Apples

  • Peaches

  • Pears

  • Muskmelons

  • Tomatoes (if treated separately)

---

Storage Room 4: Low Humidity or Specialized Crops

• Temperature: Variable depending on crop requirements

• Relative Humidity: Moderately high but less than 90%, around 60–75%

• Vegetables Stored:

  • Onions and garlic (preferred lower RH to avoid staining and decay)

  • Winter squash and pumpkins (optimal RH ~60–70%)

  • Any crops sensitive to high humidity or requiring drier conditions

---

Rationale:

• Separation of warm- and cool-season crops avoids chilling injuries and maintains optimal storage temperature.

• Segregating ethylene-producing fruit prevents damage to ethylene-sensitive vegetables.

• Adjusting humidity prevents diseases and quality loss for specific crops (e.g., onions, squash).

• Such organization helps maximize shelf life and quality across diverse crops.

This layout balances practical storage with crop physiological needs and market requirements.

What are some common methods of cooling vegetables? Provide an example of a vegetable that might be best cooled by each method.

1. Passive Storage (Root Cellars, Earth-Buried Storage)

• Description: Uses natural underground or insulated spaces to moderate temperature without mechanical refrigeration.

• Example Vegetable:

  • Potatoes — store well in root cellars with stable, cool temperatures.

---

2. Refrigerated Rooms / Insulated Coolers

• Description: Enclosed, refrigerated spaces that maintain controlled temperature and humidity.

• Example Vegetable:

  • Lettuce — commonly stored in refrigerated rooms at low temperatures and high humidity.

---

3. Forced-Air Cooling

• Description: Cold air is rapidly forced through containers or pallets to quickly remove field heat.

• Example Vegetable:

  • Broccoli — benefits from rapid forced-air cooling to slow respiration and yellowing.

---

4. Hydro-Cooling

• Description: Vegetables pass through or are sprayed with cold water to quickly reduce temperature.

• Example Vegetable:

  • Leafy greens (spinach, lettuce) — hydro-cooling efficiently cools delicate, high-surface-area greens.

---

5. Vacuum Cooling / Ice Packing

• Description: Vacuum cooling rapidly removes heat by evaporative cooling; ice packing surrounds produce with ice to maintain near-freezing temperatures.

• Example Vegetable:

  • Broccoli (ice packing used in California) — ice keeps it very close to 0 °C for longer shelf life.

How does modified atmospheric storage with films work?

What impact do these films have on oxygen and carbon dioxide, and why is that important?

How Modified Atmosphere Storage with Films Works:

• Vegetables are packaged in bags or films that have specific permeability to gases like oxygen (O₂) and carbon dioxide (CO₂).

• As the vegetable respires inside the sealed or semi-sealed package, it consumes O₂ and produces CO₂.

• If the film restricts gas exchange, the O₂ concentration inside the package decreases while CO₂ concentration increases, creating a modified atmosphere around the produce.

---

Impact on Oxygen and Carbon Dioxide:

• Oxygen (O₂):
  The film lowers the oxygen level inside the package by limiting its influx and allowing respiration to consume it.

  • Lower O₂ slows down respiration rate, reducing metabolic activity and slowing deterioration.

• Carbon Dioxide (CO₂):
  The film traps CO₂ produced by respiration, increasing its concentration inside the package.

  • Higher CO₂ levels also inhibit respiration and can suppress microbial growth, extending shelf life.

---

Why is this Important?

• Managing O₂ and CO₂ concentrations optimizes storage conditions for each vegetable’s physiology.

• It extends shelf life, maintains quality, and reduces water loss and nutrient degradation.

• Different vegetables require different optimal O₂/CO₂ ranges, so selecting the appropriate film permeability tailors storage for specific crops.

In summary, modified atmosphere packaging uses controlled gas exchange through specialized films to slow respiration and spoilage post-harvest.

Fabaceae

beans peas

What is the difference between determinate and indeterminate beans?

Under what circumstances would you chose one over the other? Which would be most common for processing and why?

Determinate Beans (Bush Beans)

• Growth habit: Finite growth; plants grow to a certain size and then stop.

• Harvest: Pods tend to mature synchronously.

• Plant structure: Bushier plants, generally don’t require trellising.

• Harvest method: Suited for mechanical, large-scale harvesting.

• Market: Commonly used for processing (canned or frozen beans).

• Advantages for processing:

  • Predictable, simultaneous maturity allows a one-time mechanical harvest.

  • Easier to manage larger acreages under contracts specifying timing.

  • Efficient for large-scale growers.

Indeterminate Beans (Pole/Vining Beans)

• Growth habit: Continuous growth; produce pods over an extended period.

• Harvest: Pods mature at different intervals over time.

• Plant structure: Vining, require trellising for support.

• Harvest method: Often hand-harvested, suited to smaller-scale or fresh markets.

• Market: Mostly fresh market or small-scale production.

• Advantages for fresh market:

  • Extended harvest window allows picking small amounts regularly.

  • Better for limited space or roadside sales.

Which to Choose?

• Choose determinate beans when:

  • You need a uniform crop for mechanical harvesting.

  • You're growing for processing under contract.

  • Your operation is large scale and you want a shorter, manageable harvest period.

• Choose indeterminate beans when:

  • You're producing fresh market beans on a small scale.

  • You want continual harvest throughout the season.

  • You have limited space or prefer hand harvesting.

Most Common for Processing

• Determinate beans are most common for processing because their synchronous maturity fits the needs of mechanical harvesting and processing contracts that require timing precision.

What are typical planting and harvesting dates for beans and peas in MI?

Peas (Cool-season crop)

• Planting: Early spring, as soon as soil temperatures reach about 40°F at 2-inch depth (around early April).

• Harvesting: About 6–8 weeks after planting, so typically by early June.

• Notes: Peas are planted early to avoid heat and are sensitive to high temperatures during flowering and pod set.

Beans (Snap Beans, Warm-season crop)

• Planting: After the frost-free date to avoid damage (usually late May in Michigan).

• Harvesting: About 60 days after planting for snap beans; some varieties (e.g., lima beans) may take 75–90 days.

• Notes:

  • Processing beans may be planted later, such as in July, resulting in a September harvest to avoid hot nights that reduce pollination success.

  • Beans require warmer soil and air temperatures compared to peas.

Summary Table

Crop	Planting Time (Michigan)	Harvest Time (Approximate)
Peas (Pisum sativum)	Early April (soil ~40°F)	Early June (~6–8 weeks later)
Snap Beans (Phaseolus vulgaris)	Late May (after frost)	Late July (~60 days later)
Lima Beans (Phaseolus lunatus)	Late May to early June	July to August (75–90 days)
Processing Beans (snap)	July (late planting)	September

This staggered timing helps manage heat sensitivity and mechanical harvest windows.

What are typical plant spacings (between rows and in-rows) for beans and peas?

Beans (Phaseolus vulgaris — Snap Beans)

• Between rows: Usually about 30 inches (76 cm) — common due to grower equipment set up, especially in large-scale production linked to corn-row spacing.

• In-row spacing: Often just a few inches apart (around 2–3 inches), but exact spacing varies depending on variety and production system.

• Small-scale/specialty: Some growers use narrower row spacing (e.g., three rows on 15-inch beds) for higher density or raised beds.

Peas (Pisum sativum)

• Processing Peas (determinant varieties):

  • Between rows: Very narrow, often planted with a grain drill or mechanical seeder.

  • Row spacing: Around 7 inches (18 cm) or even less for dense plantings.

• Trellised (indeterminate) Peas (fresh market):

  • Between rows: Wider, about 3–4 feet (about 1 meter) to allow for trellising and harvesting access.

  • In-row spacing: Similar to beans, a few inches apart to allow healthy growth.

Summary Table

Crop	Between-row Spacing	In-row Spacing	Notes
Snap Beans	~30 inches (76 cm)	2–3 inches	Mechanized equipment drives spacing
Peas (Processing)	~7 inches (18 cm)	Close spacing	Dense planting for mechanical harvest
Peas (Trellised/Fresh Market)	36–48 inches (90–120 cm)	A few inches	Wider row for trellising and hand harvest

What negative effect can warm temperatures at night have on snap beans?

Warm nighttime temperatures can negatively impact snap beans primarily by reducing pollination success. Specifically:

• Warm nights during flowering cause poor pollen fertilization, leading to flower drop and poor fruit set.

• This results in fewer developed pods despite the presence of flowers and plants appearing healthy.

• The issue is particularly noticeable in regions like Michigan during late summer plantings.

• The consequence is a "beautiful" crop with many flowers but very low yield because pods don’t develop properly.

So, warm night temperatures disrupt effective pollination, which is critical for good pod formation and final yield in snap beans.

Briefly describe the key processes involved in nitrogen fixation for beans and peas. What factors can
suppress or enhance N fixation?

Key Processes in Nitrogen Fixation for Beans and Peas

• Legumes form root nodules that house Rhizobium bacteria.

• Bacteria convert atmospheric nitrogen (N₂) into usable nitrogen compounds (ammonia) for the plant.

• The plant supplies carbohydrates (sugars) to the bacteria as an energy source.

• This mutualistic exchange benefits the plant with nitrogen and the bacteria with food.

Factors Affecting Nitrogen Fixation

• Enhance N fixation:

  • Proper inoculation with Rhizobium bacteria if bacteria are not naturally present.

  • Adequate but not excessive soil moisture.

  • Good nodule development in healthy root systems.

  • Plant growing to reproductive stages (fixation peaks during pod/seed development).

• Suppress N fixation:

  • High soil available nitrogen (fertilizer) reduces nodulation because the plant reduces carbohydrate supply to bacteria when nitrogen is abundant.

  • Poor soil conditions (extreme pH, poor drainage).

  • Environmental stress (drought, temperature extremes).

  • Disease or root damage.

In short: legumes fix nitrogen via nodules housing bacteria, but excessive soil nitrogen or poor growing conditions reduce the benefit.

If beans can fix nitrogen, why is nitrogen fertilizer recommended for commercial production?

Although beans can fix nitrogen through their symbiosis with Rhizobium bacteria, nitrogen fertilizer is still often recommended in commercial production for these reasons:

• Nitrogen fixation peaks mainly during the reproductive stage (seed/pod development), but vegetable beans are often harvested early at the immature pod stage, so total nitrogen fixed may be limited.

• Young bean plants and early growth stages need available nitrogen in the soil before nodules form and fixation becomes effective.

• Environmental or management factors may limit efficient nodulation or fixation (e.g., poor soil conditions, lack of effective Rhizobium bacteria).

• Commercial production aims for high yields and consistent quality, so supplemental nitrogen can help meet early nutrient demands and reduce risk.

• Over-fertilizing reduces fixation but ensures adequate nitrogen availability — it's a trade-off producers manage.

In summary, nitrogen fertilizer helps support bean growth before fixation kicks in and ensures reliable nutrition under variable field conditions.

How do peas and beans vary in their sensitivity to pH?

Peas and beans differ in their sensitivity to soil pH as follows:

• Beans:

  • More sensitive to high pH soils.

  • High pH can cause nutrient deficiencies, especially manganese deficiency (chlorosis on young leaves).

  • Common problems in Michigan soils with elevated pH include manganese-related symptoms.

• Peas:

  • More sensitive to low pH (acidic) soils.

  • Low pH can limit availability of essential nutrients, affecting growth.

Implications

• When choosing which crop to plant, consider soil pH:

  • Avoid peas on strongly acidic soils.

  • Avoid beans on strongly alkaline soils.

• Adjust soil pH if needed to suit the crop or choose crops adapted to existing soil conditions.

What nutrient deficiencies are most common for beans?

The most common nutrient deficiency for beans, especially in Michigan soils, is manganese (Mn) deficiency, which typically occurs in high pH soils (alkaline conditions). Symptoms include:

• Chlorosis (yellowing) on young leaves, especially at leaf tips and margins.

• Necrosis or "hopper burn"-like patches that might be mistaken for insect damage.

Other nutrient imbalances can occur depending on soil conditions, but manganese deficiency is notably significant because beans are sensitive to high pH and manganese availability decreases as pH rises.

What crops/cover crops would work well in rotation with beans/peas?

Suitable Rotation Crops and Cover Crops

Crop Type	Examples	Benefits in Rotation with Beans/Peas
Grain Crops	Corn, wheat, oats	Non-legume crops that follow nitrogen-fixing legumes to use residual soil N efficiently.
Brassicas	Cabbage, broccoli, mustards	Break disease cycles, different pests.
Small grains	Barley, rye (also cover crops)	Provide ground cover, reduce erosion.
Cover Crops (Legumes)	Hairy vetch, clover, cowpeas	Add additional nitrogen fixation; useful before non-legumes.
Non-legume cover crops	Rye, oats, wheat	Improve soil structure and weed suppression.

Specific Tips

• Avoid planting beans or peas consecutively to minimize disease buildup (e.g., root rots, viruses).

• Use legumes as cover crops (e.g., hairy vetch) for nitrogen addition before heavy feeders, but allow enough time to terminate cover crops before planting vegetables.

• Rotation with corn or other cereals works well as these crops utilize nitrogen left in soil after legumes.

• Include diversity to break pest and disease cycles common in legumes.

Snap beans have shallow root systems and are fairly susceptible to drought, so why are they often grown on light soils in Michigan?

Snap beans are often grown on light, sandy soils in Michigan despite their shallow roots and sensitivity to drought because:

• Sandy soils provide better drainage and allow for more predictable, timely harvest windows.

• These soils dry out faster after rain, making fields accessible for mechanical harvesting, which is critical because snap beans have a very narrow optimal harvest window.

• Heavy or poorly drained soils can become muddy and delay harvesting; a delay of a few days can result in crop loss because the pods quickly pass their ideal stage.

• Although sandy soils require careful irrigation management to prevent drought stress, the advantage of reliable harvest timing and machinery access outweighs the drawbacks.

In essence, the benefit of facilitating mechanical harvest and harvest timing on sandy soils is prioritized over the drought sensitivity, with irrigation used to manage water needs.

What benefits do “afila” (leafless) peas have compared to regular peas?

Afila (leafless) peas have several benefits compared to regular peas:

• Reduced leaf area replaced by tendrils, which serve as climbing structures.

• Improved air circulation in the canopy, which helps reduce disease incidence.

• Better light penetration to pods and stems, leading to improved pod color (greener appearance).

• Higher planting densities possible due to reduced shading and crowding.

• Reduced need for trellising or easier climbing, since more tendrils help plants support themselves by grasping neighbors.

• Potentially higher rates of beneficial insect predation, as predators can more easily move through less dense foliage.

Overall, afila peas are bred to optimize plant architecture for better disease resistance, pod quality, and management efficiency.

CUCURBITACEAE:

Squash, Pumpkins, Melons and Cucumbers

What is the relative maturity time of different members of the cucurbit family?

The relative maturity times of different members of the Cucurbitaceae family vary somewhat, but all are generally warm-season, annual plants in Michigan, and are usually fast-fruiting to allow harvest within a single growing season (within a year). Here's a summary of maturity characteristics by genus and crop:

• Cucurbita (squash, pumpkins, gourds):

  • Typically warm-season annuals in Michigan.

  • Summer squash (e.g., zucchini, patty pan) usually mature quickly and can be harvested early in the season.

  • Winter squash and pumpkins take longer to mature but are still harvested within the same growing season. They are called "winter squashes" because they store well into winter, not because they grow then.

  • Early production is sometimes achieved using transplants and season extension (low tunnels/plasticulture).

• Cucumis (cucumbers, muskmelons/cantaloupe, honeydew):

  • Also warm-season annuals, generally maturing moderately fast.

  • Pickling cucumbers are short, stout, and fast-maturing.

  • Slicing cucumbers and some muskmelons (like cantaloupe) can have variable maturity times; early slicers may be transplanted for earlier markets.

  • Muskmelons (cantaloupes) are somewhat slower growing and often grown in warmer climates but adapted cultivars are grown in Michigan.

• Citrullus (watermelon):

  • Native to much warmer African climates, watermelon is typically the most heat-loving and cold-sensitive member of the family.

  • Mature relatively slowly compared to cucumbers and summer squash; requiring long warm seasons.

  • Watermelons require warm conditions and are very sensitive to frost or cold temperatures, so their growing season tends to start later and finish later.

Summary:

• Fastest maturity: Summer squashes (Cucurbita pepo), pickling cucumbers (Cucumis sativus).

• Moderate maturity: Winter squashes, pumpkins (Cucurbita), muskmelons (Cucumis).

• Slowest maturity: Watermelon (Citrullus), requiring longest warm season and higher temperature sensitivity.

Early maturing cultivars and season extension techniques (transplants, low tunnels) can accelerate some crops, especially summer squash and early cucumbers.

Which vegetables are in the genus Cucurbita? Cucumis? Citrullus? What part of the world are each
native to?

Genus: Cucurbita

• Vegetables:

  • Summer squash (zucchini, patty pan)

  • Winter squash (acorn, spaghetti squash, butternut, Hubbard)

  • Pumpkins (pie pumpkins, Jack-O'-Lantern pumpkins, giant pumpkins)

  • Gourds

• Native to:

  • Americas: Primarily North and Central America (wild progenitors native to these regions).

  • Domesticated around 8,000 to 10,000 years ago in this area.

---

Genus: Cucumis

• Vegetables:

  • Cucumbers (Cucumis sativus) — pickling cucumbers and slicing cucumbers

  • Muskmelons (including cantaloupe, true muskmelon, honeydew)

• Native to:

  • India and Southeast Asia.

---

Genus: Citrullus

• Vegetables:

  • Watermelon (Citrullus lanatus)

• Native to:

  • Sub-Saharan Africa, particularly warm regions.

---

This origin influences their growth needs: For example, Citrullus (watermelon) is most sensitive to cold because it evolved in warmer African climates, while Cucurbita species are better adapted to North American temperate zones. Cucumis crops are adapted to somewhat warmer but varied climates in South and Southeast Asia.

Which types of “winter squash” and “pumpkins” are Cucurbita pepo?

The types of winter squash and pumpkins that belong to the species Cucurbita pepo include:

Winter Squash in Cucurbita pepo:

• Acorn squash

• Spaghetti squash

• Other smaller winter squash types often marketed as "pie pumpkins" or similar

Pumpkins in Cucurbita pepo:

• Standard pie pumpkins (used for pumpkin pie)

• Halloween Jack-O’-Lantern pumpkins (most common orange pumpkins seen in fields)

• Other pumpkins commonly grown for fresh market and decorative purposes

Additional notes:

• Cucurbita pepo covers a wide range of fruit shapes and sizes within these categories, including summer squashes like zucchini, patty pan, and the winter/pumpkin types.

• Some pumpkins and winter squash that people commonly think of (like giant pumpkins) are actually from different species such as Cucurbita maxima or Cucurbita moschata.

So, many typical Halloween pumpkins and smaller winter squash varieties (acorn, spaghetti) are Cucurbita pepo.

Most cucurbits are monoecious. What does this mean?

Do male or female flowers usually form first?

How are female flowers usually pollinated?

What does monoecious mean?

• Monoecious plants have separate male and female flowers, but both types grow on the same individual plant.

• So one plant produces both male flowers (which make pollen) and female flowers (which develop fruit after pollination), but these flowers are distinct and separate.

---

Which flowers usually form first: male or female?

• Male flowers usually form first and appear before the female flowers.

• This is thought to be evolutionary: producing cheaper male flowers first ensures plenty of pollen is available when the more resource-intensive female flowers open.

---

How are female flowers usually pollinated?

• Female flowers are typically pollinated by insects, especially native bees and honeybees.

• Insects visit male flowers to collect pollen and then transfer pollen to female flowers while foraging.

• Female flowers often open for a short time (often just one morning) and require multiple visits (around 10–12) by pollinators to ensure good fertilization and fruit development.

• Good pollination increases seed set and fruit size, while poor pollination can cause misshapen or aborted fruits.

Which cucurbit is andromonecious? What does this mean?

The cucurbit genus Muskmelons (which is part of Cucumis) is andromonoecious.

What doesandromonoeciousmean?

• Plants produce male flowers first, followed by perfect (bisexual) flowers on the same individual plant.

• Perfect flowers contain both male (stamens) and female (pistils) reproductive organs in a single flower—meaning they can self-pollinate in theory.

• So in andromonoecious plants, you have separate male flowers early, then flowers that contain both sexes later.

This differs from the common monoecious system in most cucurbits (like pumpkins and cucumbers), where male and female flowers are separately produced on the same plant.

What are parthenocarpic varieties? Why are these desireable especially for greenhouse production?

Parthenocarpic varieties are cucurbit plants that produce fruit without the need for pollination or fertilization.

What does this mean?

• The fruit sets and develops without seeds, so pollination by insects or other means is not necessary.

• These fruits are often seedless or have underdeveloped seeds.

Why are parthenocarpic varieties desirable, especially for greenhouse production?

• Pollinator limitation: Greenhouses often lack adequate pollinator activity (such as bees), so normal fruit set can be poor without manual pollination.

• Consistency and yield: Parthenocarpic varieties can reliably produce fruit regardless of the presence or activity of pollinators.

• Labor savings: Reduces the need for hand pollination or introducing pollinators into confined greenhouse spaces.

• Improved fruit quality: Seedless fruit can be a market advantage in some cases.

Thus, parthenocarpic cultivars are preferred in environments where pollinators are limited or unavailable, making them well-suited for controlled greenhouse conditions.

Why are they not typically used for field production?

Parthenocarpic varieties are generally not widely used for field production because:

• Pollinators are usually abundant in the field: Natural pollination by bees and other insects is typically sufficient in open field environments, so the advantage of parthenocarpy (no need for pollination) is less critical.

• Seed production needed for reproduction: In field production, growers often need seed production on plants for future crops or for commercial seed sales. Parthenocarpic fruits often have undeveloped seeds or none at all, which complicates seed saving or production.

• Fruit size and quality trade-offs: Parthenocarpic fruits may sometimes have different taste, size, or texture compared to normally pollinated fruits, which might affect market preferences.

• Cost and availability: Parthenocarpic seed varieties can be more expensive and less available for large-scale field planting compared to standard varieties.

In summary, parthenocarpic cultivars are most advantageous in controlled environments like greenhouses where pollination is limited, but in open fields with abundant pollinators, traditional varieties are typically preferred for better seed production and established market qualities.

What are gynoecious cucumbers, and why are they usually sold with 10% monoecious varieties mixed
with seed?

Gynoecious cucumbers are varieties that produce mostly or exclusively female flowers on the plant.

Why are gynoecious cucumbers grown or sold?

• Having mostly female flowers means more potential fruit production since female flowers develop into cucumbers.

• This trait is particularly useful in greenhouse production, where maximizing fruit set is desirable.

Why are they usually sold mixed with about 10% monoecious varieties?

• Pollination necessity: Gynoecious plants lack male flowers making their own pollen. They still need pollen to fertilize flowers and produce fruit.

• Mixing in 10% monoecious seed ensures there are enough male flowers in the crop to provide pollen for pollination.

• Without male flowers present, fruit set would be poor because no pollen would be available.

So, the mix allows growers to benefit from the high fruit-producing female flowers of gynoecious plants while ensuring a reliable pollen source from the monoecious plants.

What are the major types of cucumbers?

The major types of cucumbers include:

1.Pickling Cucumbers

• Shorter, stouter, and faster-growing varieties.

• Primarily grown for processing into pickles.

• Michigan is a major producer of pickling cucumbers.

• Typically harvested immature (usually less than 5 inches long).

2.Slicing Cucumbers

• Longer, thinner, and more slender than pickling types.

• Grown mostly for fresh market consumption.

• Often grown in greenhouses (especially in Michigan) or in open fields in regions like southwestern Michigan.

• Harvested at full size and eaten fresh.

3.Specialty Cucumbers (e.g., Lemon Cucumbers)

• Unusual shapes or colors, such as round yellow "lemon" cucumbers.

• Often grown for niche markets or novelty purposes.

• May have different taste or yield characteristics compared to standard types.

What are the major US production regions for each type of cucumber?

1. Pickling Cucumbers

• Major production: Michigan is the top producer of pickling cucumbers in the U.S.

• Crop spread: Pickling cucumbers are grown across various regions but Michigan, with its favorable climate and strong processing infrastructure, specializes heavily in this crop.

• Typical growing areas: Mainly concentrated in the “thumb” region and other parts of Michigan with suitable soils and flat land for mechanical harvesting.

---

2. Slicing Cucumbers (Fresh Market)

• Major production:

  • Southwestern Michigan is well-known for intensive slicing cucumber production, particularly for fresh market sales.

  • Other important regions include parts of Indiana, Illinois, and the western U.S. (California) where plasticulture systems are common.

• Greenhouse production: Often concentrated in Michigan and other northern states to achieve early-season supply.

---

3. Specialty Cucumbers

• Usually grown in smaller quantities across various regions depending on market demand.

• Grown often in local or niche markets rather than a dominant geographic area.

---

Summary Map:

• Michigan: #1 for pickling cucumbers and important for fresh market slicing cucumbers and greenhouse production.

• Southwestern Michigan: Intensive fresh-market slicing cucumber production.

• Other states: Variable production of slicing cucumbers and specialties in warmer climates and from greenhouse systems.

What is the typical time to maturity of pickling cucumbers?

The typical time to maturity for pickling cucumbers is around 30 to 40 days from planting to harvest.

• They are fast-growing, short, and stout varieties bred for quick development and early harvest.

• This rapid maturity allows multiple pickings during the growing season and fits well with direct seeding and processing schedules.

How do production practices for slicing and pickling cucumbers vary? Why?

Pickling Cucumbers

• Planting method: Mostly direct-seeded in the field, often in dense plantings.

• Production scale: Usually grown on large acreages for mechanical harvesting and processing.

• Harvesting: Mechanical harvesters are common since pickles are processed. This requires uniform fruit size and density.

• Plant spacing: Denser planting to maximize yield per acre; plants mature quickly (30-40 days).

• Growing region: Often grown throughout Michigan’s “thumb” and other areas suited to mechanical harvest.

• Cultural system: More extensive with less intensive inputs compared to slicing cucumbers.

• Season extension: Less common; typically single planting with multiple harvests.

---

Slicing Cucumbers

• Planting method: Often transplanted, especially for early production, and grown on plasticulture raised beds with drip irrigation.

• Production scale: Both field-grown and greenhouse production exist, especially in southwestern Michigan for fresh market.

• Harvesting: Usually hand-harvested to ensure fruit quality and minimal damage for fresh market sales.

• Plant spacing: Wider spacing to allow larger fruit size and better airflow; less dense.

• Growing region: Concentrated in specific high-value areas like southwest Michigan and greenhouse facilities.

• Cultural system: More intensive inputs like fertigation, low tunnels for season extension, and precise pest management.

• Season extension: Common to capture premium early markets.

---

Why do they differ?

• Market use: Pickling cucumbers go to processing, so uniformity, yield per acre, and mechanical harvest matter most. Slicing cucumbers are fresh market, requiring higher quality fruit and careful handling.

• Harvest timing and fruit size: Pickling cucumbers are harvested immature and small, slicing cucumbers are larger and mature differently.

• Economic value: Fresh market slicing cucumbers command premium prices, justifying more intensive and precise management.

• Labor and equipment: Pickling cucumbers rely on mechanization, slicing cucumbers rely more on manual labor and season extension technology.

What is typical plant spacing for pickling vs slicing cucumbers?

Typical plant spacing varies between pickling and slicing cucumbers due to differences in growth habits, harvest methods, and market requirements:

Pickling Cucumbers

• Spacing: Generally denser planting, often with rows spaced about 36 to 42 inches apart, and plants spaced closer within the rows.

• Purpose: Dense spacing maximizes yield per acre for mechanical harvesting of many small fruits.

• Example: Seeds may be directly sown in rows with about 6–8 inches between plants, resulting in a high plant population.

---

Slicing Cucumbers

• Spacing: Typically wider spacing to allow room for larger fruit development and better airflow.

• Row spacing: Often around 48 to 60 inches apart (especially with plasticulture beds).

• Plant spacing within rows: Usually wider than pickling, about 12 to 18 inches apart.

• Purpose: Wider spacing supports larger fruit size and reduces disease pressure; hand-harvested, so spacing is less constrained by mechanical equipment.

---

Summary:

Crop	Row Spacing	In-Row Plant Spacing	Notes
Pickling Cucumber	36–42 inches	6–8 inches	Dense for mechanical harvest
Slicing Cucumber	48–60 inches (plastic beds)	12–18 inches	Wider for larger fruit, hand harvest

When are pumpkins generally planted in Michigan?

In Michigan, pumpkins are generally planted in late spring to early summer, typically between mid-May and early June.

• This timing ensures that pumpkins have a full warm growing season to mature before the first fall frost.

• Since pumpkins are warm-season crops sensitive to frost, planting is timed after the danger of frost has passed and the soil has warmed sufficiently (usually soil temperatures above 60°F).

• Early planting may be done using transplants or plasticulture in warmer areas to get an earlier harvest, but for most field-scale pumpkin production, direct seeding in late May to June is standard.

What problems can high temperatures cause in cucumbers?

High temperatures can cause several problems for cucumbers, including:

1.Reduced Pollinator Activity

• Bees and other pollinators may be less active during very hot weather, leading to poor pollination.

• Poor pollination can result in misshapen, small, or aborted fruit.

2.Heat Stress on Plants

• Excessive heat can stress plants, potentially reducing growth rates and overall vigor.

• Heat stress can also cause flower drop, especially female flowers, reducing fruit set.

3.Fruit Quality Issues

• High temperatures can negatively affect fruit development, resulting in smaller or lower-quality cucumbers.

• Heat stress may cause bitterness or deformities.

4.Increased Water Demand

• High temperatures increase transpiration and water needs, so inadequate irrigation can lead to stress or fruit quality problems.

---

Summary: High temperatures threaten cucumbers mostly by reducing pollination effectiveness and causing stress that affects fruit set, size, and quality. Managing water and supporting pollinators are key under such conditions.

What are some common nutrient deficiencies seen in cucurbit crops?

Common nutrient deficiencies observed in cucurbit crops include:

1.Manganese (Mn) Deficiency

• Occurs especially in soils with high pH (above 6.5), which reduces Mn availability.

• Symptoms may include interveinal chlorosis (yellowing between leaf veins) on young leaves, and reduced growth.

• Growers may apply manganese supplements when pH is high.

2.Nitrogen (N) Deficiency

• Causes pale green to yellowing of older leaves and overall reduced growth.

• Nitrogen is essential but over-application should be avoided as excessive N leads to excessive leaf growth with poor fruit development.

3.Potassium (K) Deficiency

• Symptoms include leaf margin chlorosis and necrosis (leaf edges turning yellow and brown) and weak stems.

• Potassium is important for fruit quality and stress resistance.

4.Phosphorus (P) Deficiency

• Can cause stunted growth and dark green or purpling leaves, especially early in the season.

---

Managing fertility with balanced N-P-K and micronutrients like manganese is important, and soil testing helps tailor fertilization. Side-dressing nitrogen around the "tip-over" growth stage optimizes uptake and fruit development.

What are the recommendations for “curing” winter squash?

Curing winter squash is an important post-harvest step to improve storage life and flavor. Here are typical recommendations for curing winter squash:

Curing Recommendations:

• Temperature: Keep squash at a warm temperature around 80 to 85°F (27 to 29°C) during curing.

• Duration: Cure for about 7 to 10 days after harvest.

• Humidity: Maintain relatively high humidity (80–85%) to prevent shriveling but avoid wetness that promotes rot.

• Purpose:

  • Hardens the skin, which reduces water loss and disease entry.

  • Allows starches to convert into sugars, improving flavor and sweetness.

  • Heals minor cuts or bruises on the rind, extending storage life.

---

After Curing:

• Move squash to cool, dry storage at about 50 to 55°F (10 to 13°C) with good ventilation.

• Proper curing and storage can prolong shelf life for several months through the winter.

Row covers are often used for protection against cucumber beetles on organic farms. If not managed
correctly, name several problems the row covers cause.

When using row covers for cucumber beetle protection on organic farms, improper management can lead to several problems:

Potential Issues with Row Covers if Not Managed Correctly:

1. Reduced Pollination:

   • Row covers physically block pollinators (bees and other insects) from accessing flowers.

   • Without timely removal or intervention, this can cause poor pollination, leading to misshapen or aborted fruit.

2. Increased Heat and Humidity:

   • Row covers can trap heat and moisture, potentially causing overheating or high humidity conditions that stress plants or promote diseases.

3. Delayed Flowering or Fruiting:

   • Excessive heat or poor air circulation under covers may slow plant development.

4. Pest Build-up:

   • Row covers can sometimes trap pests inside or create favorable microclimates for other pests or diseases if not monitored and rotated properly.

5. Labor Intensive Management:

   • Requires careful timing to remove covers when pollinators are active, which can be laborious and easy to mistime.

---

Key management tip:

Remove row covers during flowering periods or provide alternative pollination methods (like hand pollination) to avoid fruit set issues.

What are optimal storage conditions for different cucurbit crops?

Here are the optimal storage conditions for key cucurbit crops:

Crop	Storage Temperature	Relative Humidity	Storage Duration (Approximate)	Notes
Winter Squash (e.g., acorn, butternut, Hubbard)	50–55°F (10–13°C)	50–70%	Several months (up to 3–6 months)	Requires curing before storage to harden skin
Pumpkins	50–55°F (10–13°C)	50–70%	Several months	Similar to winter squash; sensitive to frost
Cucumbers (fresh market)	50–55°F (10–13°C)	High (90–95%)	1–2 weeks	Cool and high humidity; sensitive to chilling injury below 50°F
Pickling Cucumbers (short-term)	50–55°F (10–13°C)	High (90–95%)	1 week or less	Processed quickly, limited storage time
Melons (e.g., cantaloupe, honeydew)	36–41°F (2–5°C)	85–95%	1–3 weeks (depending on maturity)	Sensitive to chilling; ideally precooled quickly
Watermelon	50–60°F (10–16°C)	85–90%	2–4 weeks	Sensitive to chilling injury if stored too cold

---

Summary Notes:

• Most winter squash and pumpkins prefer moderate cool temperatures (not too cold) and dry storage after curing.

• Cucumbers need cooler and very humid conditions but are sensitive to temperatures below about 50°F, which can cause chilling injury.

• Melons and watermelons require cooler storage but also are chilling sensitive and need careful handling.

BRASSICACEAE

Mustard family

How many petals do all members of mustard family have (why are they sometimes called “crucifers”)?
What are “cole crops”?

Mustard Family Petals and "Crucifers"

• All members of the mustard family (Brassicaceae) have 4 petals arranged in a cross shape.

• Because of this distinctive floral pattern resembling a cross, they were historically called "crucifers" (from Latin crucifer meaning "cross-bearer").

Cole Crops

• Cole crops refer primarily to certain vegetables within the genus Brassica oleracea.

• These include well-known vegetables such as broccoli, cabbage, Brussels sprouts, kale, cauliflower, and kohlrabi.

• They are grouped together because they are different cultivars bred from the same species, focusing on different edible parts (flowers, leaves, stems, etc.).

Provide several reasons why so many vegetables in the mustard family are grown over the winter in the passive solar greenhouses in Michigan?

Here are several reasons why many mustard family vegetables are grown over the winter in passive solar greenhouses in Michigan:

• Cold Tolerance: Most Brassicaceae crops are cool-season plants that tolerate frost well. Many are biennials or winter annuals capable of surviving cold temperatures and even snow cover.

• Winter Annual Weeds: Wild mustard family species often germinate in the fall, survive the winter as rosettes under snow, and then grow rapidly in early spring, showing their adaptation to cold seasons.

• Extended Season: Passive solar greenhouses provide some protection and moderate temperatures, enabling these cool-season crops to continue growing through winter when outdoor conditions are too harsh.

• Economic Niche: Growing these crops in winter meets market demand for fresh vegetables when field-grown produce is unavailable, giving growers a valuable off-season crop.

• Plant Physiology: These plants have mechanisms (e.g., slow growth as rosettes) that allow them to withstand winter stress and resume active growth when conditions improve.

What are some disadvantages of growing so many mustard species?

Some disadvantages of growing many mustard family (Brassicaceae) species include:

• Pest Pressure: Mustard family crops share many of the same specialist insect pests that can detoxify their glucosinolates. This makes pest management challenging since pests often adapt specifically to these crops.

• Disease Issues: Common diseases like black rot and Alternaria often affect multiple brassica species, and pathogens can survive on crop debris or seed, increasing disease carryover risk.

• Weed Challenges: Mustard-family weeds are difficult to control chemically in cole crops because herbicides that affect weeds from the same family could also harm the crop.

• Allelopathic Compounds: The mustard oils (isothiocyanates) released upon tissue damage can affect sensitive succeeding crops negatively if crop rotation and timing aren’t managed well.

• Nutrient Management Sensitivity: High nitrogen requirements and sensitivity to micronutrient imbalances (like boron and calcium) can lead to quality problems such as hollow stem in broccoli or tip burn in cauliflower.

• Climate Limitations: Although cold tolerant, many brassicas are not heat-tolerant and struggle with summer heat, limiting season length especially in warmer climates.

What are “glucosinolates” and why are they of interest for management of vegetables?

What Are Glucosinolates?

• Glucosinolates are naturally occurring secondary metabolites in mustard family plants.

• They are stored in the vacuoles of plant cells in an inactive form.

• When the plant tissue is damaged (e.g., by chewing insects, mowing, or chopping), an enzyme is activated that converts glucosinolates into mustard oils (including compounds like isothiocyanates).

• These mustard oils are toxic or deterrent to many herbivores and pathogens.

Why Are They of Interest in Vegetable Management?

• Plant Defense: They provide the plant with a chemical defense mechanism against generalist insect pests and some microbial pathogens.

• Allelopathy/Biofumigation: When mustard-family cover crops (like oilseed radish or mustards) are grown and then incorporated into soil (mowed or chopped), the glucosinolate breakdown products act as natural biofumigants, helping suppress soil-borne pests, pathogens, and weeds.

• Crop Rotation Considerations: Because these compounds can affect sensitive crops, growers must carefully time and plan rotations after mustard cover crops to avoid negative effects on subsequent crops.

• Human Health: Some glucosinolate breakdown products found in crops like broccoli have been studied for potential antioxidant and anticancer benefits (though these require cautious interpretation).

Name 5 vegetables for which the species name is Brassica oleracea.

Five vegetables with the species name Brassica oleracea are:

1. Broccoli

2. Cabbage

3. Kohlrabi

4. Brussels Sprouts

5. Kale

These are all cultivars of the same species but bred for different edible parts (flowers, leaves, stems, buds).

What other important vegetables are in this family and what is their Genus?

Other important vegetables in the mustard family (Brassicaceae) and their genera include:

Vegetable	Genus
Bok choy	Brassica (Brassica rapa)
Mizuna	Brassica (Brassica rapa)
Tatsoi (Hansai Thai)	Brassica (Brassica rapa)
Rutabaga	Brassica (Brassica napus)
Mustards (e.g., yellow mustard)	Sinapis / Brassica napus
Radish	Raphanus
Horseradish	Armoracia

These genera provide a range of leafy greens, root vegetables, and specialty crops within the family. Let me know if you want details on any of these!

What nutrient deficiencies are common with mustard family vegetables?

Common nutrient deficiencies in mustard family (Brassicaceae) vegetables include:

• Calcium Deficiency:

  • Leads to disorders such as tip burn (e.g., in cauliflower) and internal damage like dried leaves inside Brussels sprouts.

• Boron Deficiency:

  • Contributes to problems like hollow stem in broccoli and cabbage, negatively impacting quality.

• Magnesium Deficiency:

  • Can occur especially at low soil pH, affecting overall plant health.

• Manganese Deficiency:

  • More common at high soil pH, affecting leaf health and yield quality.

Routine soil testing and monitoring, along with appropriate soil amendments and foliar feeding, help prevent these deficiencies and maintain crop quality.

Why does California produce so much of all the broccoli grown in the US?

California produces most of the broccoli grown in the U.S. because of several favorable factors:

• Climate Diversity: California offers a range of climate zones—from desert areas like the Imperial Valley for cool winter production to coastal areas with consistent cool temperatures in summer—ideal for broccoli growth year-round.

• Extended Growing Season: This allows growers to produce broccoli in winter and spring when other regions cannot.

• Irrigation Infrastructure: Reliable water supply supports large-scale production.

• Proximity to Markets: Close access to large consumer markets on the West Coast reduces transportation time and preserves freshness.

• Established Grower Networks: Well-developed agricultural systems and expertise in broccoli cultivation.

These factors combined make California uniquely suited to produce large volumes of high-quality broccoli throughout the year.

Provide several reasons why cabbage production might be less concentrated in a single region/state
compared to broccoli?

Several reasons why cabbage production is less concentrated in a single region or state compared to broccoli include:

• Better Storability:

  • Cabbage stores well for long periods, often through fermentation (e.g., sauerkraut), allowing it to be transported and marketed from a wider range of production areas without rapid spoilage.

• Broader Climate Adaptability:

  • Cabbage can be grown successfully in a variety of climates and soil types, enabling dispersed production.

• Lower Refrigeration Dependence:

  • Unlike broccoli, which is perishable and benefits from cold supply chains concentrated near consumer centers, cabbage's longer shelf life reduces pressure to grow it near major markets.

• Cultural and Regional Demand:

  • Cabbage is incorporated into many traditional diets worldwide, encouraging localized production adjusted to regional consumption patterns.

• Processing Industry Distribution:

  • Cabbage processing facilities (for sauerkraut, kimchi, etc.) may be located in various regions, further decentralizing production.

Together, these factors favor more geographically diverse cabbage production compared to the concentrated, climate-dependent broccoli industry.

What is a typical transplant production schedule for spring and fall produced cole crops in Michigan
(when are they sown, transplanted and harvested)?

A typical transplant production schedule for spring and fall cole crops in Michigan is:

Spring Production

• Seed Sowing (Greenhouse): Early to mid-March

• Field Transplanting: Late April through May

• Harvest: Mid to late June through August, depending on the crop

Fall Production

• Seed Sowing (Greenhouse): Late April to early June (to time for fall transplanting)

• Field Transplanting: Late June

• Harvest: Late summer through November

Notes

• Using high tunnels can extend the fall production season, allowing transplanting as late as mid to late July and harvesting into December.

• This schedule applies mainly to cole crops like broccoli, cabbage, and Brussels sprouts grown in Michigan's climate using transplant systems.

Let me know if you want a more detailed calendar including specific crop differences!

In California, cole crops are often direct seeded. What are the advantages of this method?

Why might there be a trend towards more use of transplants in CA?

Advantages of Direct Seeding Cole Crops in California

• Better Root Development: Direct seeded plants often develop deeper, more robust root systems, improving drought tolerance and nutrient uptake, especially in sandy soils.

• Lower Labor Costs: Eliminates the need for greenhouse raising of transplants and transplanting labor, reducing overall production costs.

• Larger Acreage Suitability: Enables growers with extensive land and limited labor to establish large plantings more efficiently.

• Simplified Scheduling: Direct seeding can simplify timing by reducing steps in production.

Reasons for Trend Towards More Use of Transplants in California

• Improved Stand Uniformity: Transplants allow better control over plant spacing and density, resulting in more uniform crops and potentially higher yields.

• Earlier Market Entry: Transplants provide an early growth advantage, allowing crops to mature sooner and reach markets earlier.

• Higher Value Markets: For growers targeting premium markets that demand uniform, high-quality produce, transplants can improve consistency.

• Labor Availability: In some regions, increasing availability or mechanization of transplanting reduces the labor cost disadvantage.

• Pest and Weed Management: Transplants can help reduce weed pressure and limit early-season pest exposure by establishing stronger seedlings before field exposure.

What problems can occur if excess nitrogen is applied to broccoli or cabbage?

xcess nitrogen application to broccoli or cabbage can cause several problems:

• Rapid, Excessive Growth:

  • Leads to overly fast vegetative growth, which can reduce quality and marketability.

• Broccoli Hollow Stem:

  • Excess nitrogen combined with heat and wide plant spacing can cause the central stem in broccoli to develop a hollow cavity, which is an entry point for pathogens and reduces product quality.

• Cabbage Head Splitting:

  • Over-fertilized cabbage heads may grow too quickly and split open, making them unmarketable and prone to decay.

• Increased Susceptibility to Diseases:

  • Rapid growth and tissue softness can encourage disease development.

• Wasted Inputs and Environmental Impact:

  • Excess nitrogen not used by the plant can leach into groundwater or volatilize, causing pollution.

Managing nitrogen carefully, monitoring crop growth, and avoiding excessive irrigation can help prevent these issues.

What are the major insect pests of cole crops, and how can they be managed?

Excess nitrogen application to broccoli or cabbage can cause several problems:

• Rapid, Excessive Growth:

  • Leads to overly fast vegetative growth, which can reduce quality and marketability.

• Broccoli Hollow Stem:

  • Excess nitrogen combined with heat and wide plant spacing can cause the central stem in broccoli to develop a hollow cavity, which is an entry point for pathogens and reduces product quality.

• Cabbage Head Splitting:

  • Over-fertilized cabbage heads may grow too quickly and split open, making them unmarketable and prone to decay.

• Increased Susceptibility to Diseases:

  • Rapid growth and tissue softness can encourage disease development.

• Wasted Inputs and Environmental Impact:

  • Excess nitrogen not used by the plant can leach into groundwater or volatilize, causing pollution.

Managing nitrogen carefully, monitoring crop growth, and avoiding excessive irrigation can help prevent these issues.

Why might it be important to manage mustard family weeds where cole crops are grown?

Managing mustard family weeds in fields with cole crops is important because:

• Herbicide Limitations:

  • Mustard family weeds have similar herbicide tolerances as cole crops, making selective chemical control difficult without damaging the crop.

• Competition:

  • These weeds compete with crops for nutrients, water, and light, reducing crop growth and yields.

• Disease and Pest Reservoirs:

  • Mustard family weeds can harbor pests and diseases that also affect cole crops, increasing infection and infestation risks.

• Seedbank Management:

  • Preventing these weeds from seeding reduces future weed pressure and long-term management challenges.

• Allelopathic Effects:

  • Some mustard family weeds release bioactive compounds that may interfere with crop growth.

Due to these challenges, integrated weed management including mechanical cultivation and careful crop rotation is essential in cole crop production.

What crops/cover crops can work well in rotation with cabbage/broccoli?

Good crops and cover crops to rotate with cabbage and broccoli include:

Companion or Rotation Crops

• Non-Brassicaceae Vegetables:

  • Avoid other mustard family crops to reduce pest and disease carryover. Examples:

    • Celery

    • Onions

    • Carrots

    • Lettuce

• Root Crops (often direct-seeded):

  • Radishes and turnips work well in rotations, especially in muck soils.

Cover Crops for Rotation and Biofumigation

• Legumes:

  • Clover and vetch add nitrogen to the soil and do not host the same pests as brassicas.

• Grasses:

  • Rye, oats, and barley help improve soil structure and compete with weeds.

• Mustard Family Cover Crops (used carefully):

  • Oilseed radish and mustards can suppress weeds and soil pathogens via glucosinolate breakdown but require careful timing before planting sensitive crops.

Rotation Benefits

• Reduce pest and disease pressure specific to Brassicaceae.

• Improve soil fertility and structure.

• Interrupt weed cycles.

What are the ideal storage conditions for broccoli and cabbage, and approximately how long can each be stored under those conditions?

Ideal Storage Conditions and Storage Duration

Crop	Ideal Temperature	Relative Humidity	Approximate Storage Duration
Broccoli	32°F (0°C)	90-95%	About 1–3 weeks
Cabbage	32°F (0°C)	90-95%	Several months (up to 3-4 months)

Notes:

• Broccoli is highly perishable; it requires very cold temperatures and high humidity to maintain quality but generally lasts only a few weeks.

• Cabbage has a dense leaf structure and stores much longer, making it suitable for extended storage and fermentation (e.g., sauerkraut).

• Both crops are sensitive to ethylene gas; exposure should be minimized to reduce yellowing and quality loss.

• Proper ventilation and temperature control are essential to prevent decay.

APIACEAE

Carrots, Parsnips, Celery

What are the main types of carrots (based on shape)?

What type of carrot do most “baby carrots” come from?

What is the earliest typical planting date for carrots and celery in Michigan?

Approximately how long does it take for carrot seeds to germinate under cool spring conditions (50-
60F)?

What conditions promote bolting in carrots? What is meant by the “juvenile period” of carrots?

What are some factors that cause forking in carrots?

What factors promote cracking of carrots?

Why is barley or wheat often sown with or before carrots (and onions) in Michigan?

What is the native habitat of celery/carrots?

Where was celery first grown in the U.S.?

Why is celery often grown on muck soils in MI?

What are some problems associated with celery seed germination?

Why is celery usually transplanted?

How much nitrogen is typically applied to carrots versus celery?

What is a “stale seedbed” and how is it used to manage weeds in carrots?

What causes “Aster yellows” in carrots/parsnips/celery, and what are some strategies for managing it?

AMARYLLIDACEAE

Onions and garlic

What genus accounts for most of the vegetables in the Alliaceae family?

What are some key characteristics of the Alliums?

What is a bulb? Clove?

What is a “long-day” plant? What is meant by the “critical daylength” of a long-day plant?

If you tried to grow an onion adapted to Texas in Michigan, what would happen?

What other vegetables have strong daylength responses?

Are summer annual weeds usually short-day or long-day for flowering? What about winter annual
weeds?

What are the major types of onions?

When are onions usually planted and harvested in Michigan?

When is garlic usually planted and harvested in Michigan?

How do thrips affect onions in Michigan and how can they be managed? What other crops are
sometimes affected by thrips?

How are onions treated after harvest? What are the optimal storage conditions for onions?

ASPARAGUS & RHUBARB

What economic and biological factors have led to the historic decline of US asparagus production?

What factors have led to a slight rebound in Michigan asparagus production?

What botanical family does rhubarb belong to, and what other crops or weeds are in that family?

Why is root carbohydrate storage so important for asparagus and rhubarb, but not for most other
vegetable crops we have studied?

Explain what happens to levels of carbohydrates in roots during the life cycle of asparagus and rhubarb.

What happens to next year’s yield if asparagus or rhubarb were harvested into June or July?
What is an asparagus “crown”/”fern”?

Describe how asparagus crowns are produced in nurseries, and the steps required to establish asparagus from crowns the following spring.