Horticulture Exam 3

How are orchids primarily classified?

By their flowering, as they belong to the family ‘Orchids’ with parallel leaves and flower parts in multiples of three.

What is mycoherbicide?

Fungal herbicides that may apply spores of fungus to control weeds.

How are weeds mechanically controlled?

By milling, mulching, soil solarization, cultural control, and biological control using organisms.

What is allelopathy?

The secretion of toxic chemicals by plants to inhibit the growth of surrounding plants.

What is an example of a physical growth habit in plants?

Prostrate, climbing, or erect growth habits.

What is the significance of velamen in orchids?

Velamen is a spongy tissue on the outer root that absorbs water.

How does light affect plant nutrition requirements?

More light increases photosynthesis and thus increases nutritional needs, depending on species.

What is the difference between epiphytic and terrestrial orchids?

Epiphytic orchids cling to other plants or surfaces for nutrients, while terrestrial orchids grow directly out of the soil.

Why is container choice important for houseplants?

Plastic and ceramic pots retain moisture better, while terracotta pots allow for better gas exchange.

What is germplasm?

The sum total of a plant’s genes.

What are some reasons to grow interior plants?

Aesthetics, personal wellness, hobby, air purification, cultural significance, food, and as something to care for.

Do houseplants share similar environments natively as they do at home?

No, most houseplants are native to regions with environments very dis-similar to those found within a home.

Indoor Environmental factors

Light, temperature, relative humidity, water, nutrition, soil, pest management, and window direction.

Footcandle

amount of light cast by a candle on a white surface one foot away in completely dark room

Interior Lightining- what is considered a sunny light area?

an area with at least 4 hours of direct sunlight

What are symptoms of overexposure to light in plants?

Upright leaves and bleached, scorched leaves

What is light compensation point?

The light intensity at which the rate of photosynthesis equals the rate of respiration.

Which windows are the best?

Eastern exposure provides the best light and temperature conditions since plants receive direct morning light from sunrise until early midday (sun rises in east, sets in west).

Southern and Western Window Light Exposures

Southern and western exposures are interchangeable for most plants. In the summer, when the sun is farther north than it is in the winter, the sun rises at a sharp angle in the morning and is high by noon so direct sunlight comes into a south window only at midday. In the winter, the sun is lower and shines into south windows for a longer duration, providing adequate light for plants. Most, plants, except those with definite preference for northern exposure, can be placed in a room with southern exposure.

What exposure is best for plants with green foliage?

Northern exposure is often best, as it provides indirect and low light levels, causing the coloration on variegated foliage to disappear under the low-light conditions. (optimal for plants like african violet).

How to tell if your plants is not receiving adequate light?

The plant does not grow, the internodes on the new growth are much longer than the internodes on the older part of the plant, the new leaves are smaller than the older leaves, the older leaves are dead, and the leaf color is a lighter green on the newer foliage than on the older foliage.

Best temperature for indoor plants?

Most people keep their indoor plants between 72 to 82 F but indoor plants can thrive between 58°F and 86°F since most originate from tropical or subtropical areas of the world.

How are temperature and light linked?

Temperature and light are linked through the processes of photosynthesis and respiration.

What is chill damage?

When temperatures drop below 50F, chill damage can result on some sensitive foliage plants and is manifested with the yellowing of lower leaves and/or defoliation.

Relative Humidity: Native vs. Household Humidity

Most houseplants are native to tropical regions where high humidity is common. Greenhouse relative humidity is higher than household relative humidity so rapid transpiration and water loss may occur when plants are moved directly from areas of high humidity to areas of low humidity.

How to increase relative humidity:

Place plants close together, use shallow containers filled with water and lava rocks/ gravel, and use humidifier/ mister

Water quality of indoor plants

fluorine and chlorine in irrigation water can cause marginal leaf chlorosis and leaf scorching

How to alleviate fluorine and chlorine damage in plants?

Let water stand for several days so that. some of the chlorine and fluroine will be released from it before it is applied to plants.

Watering Issues in Indoor Plants

Overwatering can cause stagnant moisture to foster pathogens that can damage roots.

What is best kind of watering for indoor plants?

Watering should be deep and infrequent to encourage deeper root development into sooil and preventing oversaturarion issies.

Light intensity and Nutrients

The higher the light levels, the more nutrients needed for growth

How to increase pH of soil/growing media.

Suitable media had pH of 5-6.5. To increae pH, limestone or calcium carbonate/ magnesium carbonate can be added. pH will be neutralized and Ca+ and Mg ions are provided.

Perlite

Inert and neutral pH, increases porosity and air spaces in soil and provides structure for roots

Vermiculite

Heat-expanded mica that is sterile, inert, with neutral pH. Increases soil porosity and airspace. It is lightweight and ideal for plants being shipped. Often used as covering for new seedlings and can compact, leading to increased water holding.

Peat

Mined from ancient bogs in the sub-artic. Organic and highly acidic but can decompose over time. Increase water holding capacity and provides organic matter and some nutriients.

Coconut coir

Heat treated and milled husks of coconut fruit harvest. Like peat but less acidic. Increases water holding capacity and provides structure. More aeriated and less water retention than peat.

Pine bark

Organic, acidic, and stable for longer periods. Increase pore space and aeration, and provides structure to roots. Heavy when dry so can support larger plants.

What is acclimatization in plants?

The adaptation of a plant to a new environment

What is the light compensation point in plants?

The light intensity in which the rate of photosynthesis is equal to the rate of respiration. This point will vary with species of plants, temperature, and acclimation to changes in light environment.

Methods for Light Acclimation

Gorw plants in greenhouse under shade for entire production period or grow plants at high light intensities, but acclimatize plants for 4-6 weeks at very low light intensities in a heavilty shaded greenhouse or lighted warehouse.

Glazed vs Unglazed Pots

Ungazed pots evaporate water faster so plants may need more frequent watering.

When do soil-borne disewases mostly occur?

When the growing medium is kept excessively mosit and fertility levels are high

Reasons to prune

Remove dead tissue, stop spread of disease., Increase structural integrity of tree/shrub, Aesthetics and shaping, Increase airflow to reduce disease issues.

what to prune out

Crossing limbs, Dead branches, Poorly angled branches, Water sprouts/epicormic shoots, suckers

Types of pruning cuts:

• Heading back: Topping/shaping of the total size of the plant; breaks apical dominance and encourages bushier growth

• Thinning out: Structural pruning that opens the canopy up, allowing airflow and sun penetration that initiates stronger growth and more flowering

Things to avoid when pruning:

• Stub cuts

• Large surface area cuts 

• Taking off more than necessary.

What is the 3 stage pruning cut, order of operations, and purpose?

How to plant tree:

• Dig hole larger than root ball

• Break up roots, expose root flare/collar (be able to explain why the root flare/trunk should not be buried)

• Cut girdling roots (be able to describe girdling roots)

• Plant (in spring or fall) with the root flare at the soil line, and mulch in a donut, not a volcano

• Water regularly for the first year of establishment because bigger trees have little roots so water more early.

What does trees heal dont seal mean?

floral design proportions

floral design balance

floral design dominace

floral design rythmn

floral design repitition

floral design radiation

floral desing transition

four princioples of floral deisng

proportion, balance, dominance, and rythmn