Horticulture Exam 2

Contrast Climate vs. Weather

Climate: long term characteristic of a region over time (the average)

Weather: the state of factors like temp, moisture, and wind at a specific moment.

What is a microclimate?

A small, localized area where environmental conditions (temp, light, moisture, wind) differ from the surrounding general climate.

How does elevation create a microclimate?

The higher the elevation, the cooler the temperature.

How do raised beds modify a microclimate?

They heat up and cool down much quicker than surrounding flat soil surfaces.

3 ways plants create microclimates.

1. Reduce wind speed

2. Create shade

3. Raise humidity beneath them

4 harms of low water availability (Water stress)

1. Stunted growth

2. cessation of photosynthesis

3. poor pollination

4. nutrient deficiency

4 benefits of low water availability

1. Concentrated fruit flavor

2. Increased essential oils

3. Longer shelf life

4. Faster ripening

What are the 3 phases of soil?

1. Solid (Minerals/Organic matter)

2. Liquid (Water/minerals)

3. Gas (N2, O2, CO2

What is the primary role of Sand, Silt and Clay?

Sand - adds porosity

Silt - adds body

Clay - adds chemical/physical properties (like CEC)

What is field capacity (FC)?

The moisture retained in soil after free drainage by gravity has stopped.

What is permanent wilting point (PWP)?

The soil water content at which plant growth ceases.

What is total available water (TAW) and its formula?

The difference between FC and PWP.

TAW = FC - PWP

What is the average summer evapotranspiration (ET) rate?

Approx. 0.25” per day or more.

What four factors affect the ET rate?

1. Radiation

2. Humidity

3. Air Temperature

4. Wind Speed

Define soil texture.

The composition of soil based on particle size (% sand, % silt, % clay)

Define soil structure.

The arrangement of soil particles, pores, and aggregates (clumps) within a soil body.

When is the best time to irrigate and why?

Early in the day to minimize evaporation loss and allow leaves to dry (limiting disease)

Compare flood vs. furrow irrigation.

Flood: for water-tolerant crops (rice)

Furrow: conserves more water and is common for vegetables.

3 advantages of drip irrigation?

1. Most water-efficient

2. Prevents stress (frequent/low-volume)

3. Keeps foliage dry (reduced disease/food safety risk)

3 disadvantages of drip irrigation

1. High setup/removal labor.

2. Plastic waste (replace lines annually)

3. Lines easily damaged by rodents/tools

How does Soil Type affect irrigation frequency?

Sandy soils drain freely and need more frequent watering; clay soils retain water longer.

What is the purpose of wood mulch?

Conserves moisture, improves infiltration, suppresses weeds, and increases organic matter. (High carbon can temporarily withdraw nitrogen)

What is the primary benefit and problem of clear plastic mulch?

Benefit: greatest increase in soil temp (good for solarization)

Problem: weeds can grow underneath it.

Define light intensity: compensation vs. saturation

Compensation Point: Photosynthesis matches respiration.

Saturation point: extra light no longer increases photosynthesis.

What are the effects of Blue vs. Red light?

Blue: promotes vegetative growth

Red: prompts flowering.

Define short-day vs long-day plants.

Short-day: bloom with < 12 hours light (mums, poinsettias)

Long-day: bloom in summer/long days (spinach, lettuce)

What is a USDA Cold Hardiness Zone?

A system based on the average annual minimum winter temperature to determine which plants can survive in a region.

Define plant propagation.

The art and science of multiplying plant material to preserve a given trait.

List 2 pros and 2 cons of seed (sexual propagation)

Pros:

1. Genetic diversity

2. Cheaper

Cons:

1. Slow maturity

2. Unpredictable traits

List 2 pros and 2 cons of vegetative (asexual) propagation

Pros:

1. Genetically identical “clones”

2. Fixes specific traits

Cons:

1. Relies on living parents

2. Can be expensive

Name 5 methods of vegetative propagation

1. Cuttings

2. Grafting

3. Layering

4. Tubers/Bulbs/Rhizomes

5. Tissue Culture

What are the 5 basic requirements for seed germination?

1. Water

2. Oxygen

3. Temperature

4. Light

5. Lack of chemical dormancy

Why do seeds disperse in Space vs. Time?

Space: to avoid competition and to colonize new areas.

Time: to wait for better seasons via dormancy (seed banks)

List 4 components of greenhouse anatomy

1. Glazing (clear walls)

2. Vents/Fans (air exchange)

3. Benches (air circulation)

4. Heaters

What are the 3 main reasons for greenhouse production?

1. Avoid seasonality (winters)

2. Extend existing seasons

3. Grow high-value plants in a regulated environment

What does a Soil Test typically measure?

6.0 to 7.0, it balances nutrient availability with CEC storage.

How much water can soil store per foot of depth?

1.5” to 2.5” of water per foot of depth.

Is the flooding of cranberry bods considered a method of irrigation?

No. while they are flooded for harvest/protection, flooding cranberry bods is not a method of irrigation.

How does furrow shape change based on soil texture?

Sandy soil: deep, narrow furrows.

Clay soil: wide, shallow furrows.

What is fertigation?

The process of applying fertilizers directly through an irrigation system (common in drip irrigation)

Why is a water filter required for drip irrigation?

To prevent the small emitters from clogging with sediment or minerals.

What type of cell division is used in asexual propagation?

Mitosis

List 3 reasons for genetic “shuffling” or variability in seeds.

1. Genetic shuffling (recombination)

2. Mixed parents

3. Hidden (recessive) traits

Provide an example of Temperature affecting germination from the notes.

Goosegrass seed germination

List 5 features that encourage seed dispersion over space.

1. wings and parachutes (wind)

2. hooks and barbs (animals)

3. tasty fruit (digestion)

4. buoyancy (water)

5. explosive pods (self-propelled)

List 4 input differences unique to greenhouse vs field production

1. growing substrate.

2. pots/containers

3. supplemental light

4. heating/cooling electricity

Name two common summer annuals produced in greenhouses mentioned in the activity.

1. Petunias

2. Marigolds

What is “soil solarization”?

Using clear plastic mulch to trap intense heat in the soil to kill off weeds and soil-borne pathogens before planting.

Water are “Day-Neutral” plants? Give 4 examples.

Plants that flower regardless of the length of daylight.

Ex: tomatoes, corn, cucumbers, and some strawberries.

Aside from helping gardeners, what is a major economic use for USDA Cold Hardiness Zones?

They set the standards for crop insurance, determining where nursery crops can be insured for growing outdoors.