HORT 101 - exam 4

three ways to maximize light intensity

1. use greenhouse coverings that allow max light transmission 2. properly design greenhouse 3. routinely cleaning and maintaining coverings

background info

DIF range less than 8 degrees F bottom heat helps

infrared radiant heaters

advantages - conserves energy and has no problems with pollutants disadvantages - initial higher cost, air temp regulator is more difficult, sources of radiation must be located directly above plant or pockets of low temp may occur

attached greenhouse

attached to an existing structure

positive DIF

day temp higher than night temp

thermoperiodism

plants response to changes in day and night temperature

heating systems commonly used in greenhouses

steam heating systems - water is heated to temperatures 212-215 degrees F, small pipes transport steam over long distances through greenhouse, efficiently used in large greenhouses hot water heating systems - typically used in smaller greenhouses, requires large pipes (disadvantage), difficult to transfer water over long distances without losing heat forced air heaters - uses localized heater units that force air directly into greenhouse or through long perforated tubes each system besides radiant system uses a fuel of some sort

greenhouse

structured cover with transparent material that allows sufficient sunlight to enter for the purpose of growing and maintaining plants

topography

surface features of an area land should be leveled (slope of 1 to 2% for drainage)

greenhouse environment

temperature light air humidity water

environmental factors

temperature light rainfall wind soil texture, drainage, topography and fertility water air pollution plant pest

disadvantages of connected greenhouses

the difficulty with accommodating different crops when crops require different environmental conditions

light quality

the wavelength or color of light dramatic effect on photosynthesis and can also affect shape red and blue light required for photosynthesis - shorter and darker green effects of far-red and red light on plant growth - long into nodes, less branched, and taller

rooting containers

three examples of rooting containers made from organic materials 1. peat pellets 2. peat plugs 3. peat pots

selecting containers for crops

three main materials used to produce pots 1. clay 2. plastic 3. Styrofoam clay pots - advantages (clay is natural porous material that allows water to evaporate, heavier, stronger, and can support large plants without falling over) and disadvantages (more expensive, bulky to handle and breakable, absorb mineral salts, pot bound growth occurs more rapids, when reusing, clean properly)

photoperiodism

total light energy that effects plant growth and development of plants

hygrometer

used to measure humidity

how to overcome problems with low humidity

using commercial humidifier units good watering practices

attached (pictures)

wall mounted lean-to even span should be included with initial design of house, or should be well designed if added later typically found in homes, garden centers, etc.

humidity

water vapor in air and is linked to temperature

four factors that determine the type of basic greenhouse structure used

1. space available 2. types of plants to be grown 3. geographical locations 4. cost of construction materials

satisfactory humidity for house plants

60% relative humidity

automated watering systems

TCEOPS tube irrigation capillary mat system ebb and flow method overhead irrigation perimeter irrigation soaker hose method

light intensity

actual quantity of light being supplied

solar radiation system

advantages - conserves energy and no pollutant problems, once installed they are cost effective disadvantages - high initial cost, clouds limit effectiveness

plastic pots

advantages - inexpensive, less breakable, plant roots grow more evenly, lightweight and easy to handle, come in variety of sizes and shapes disadvantages - not porous, prone to water logging, light and fall over easily, when reused they must be cleaned properly (chemical sterilization is not as effective as steam sterilization)

plastic film coverings

advantages - lightweight and can be used on wider range of greenhouse designs, variety of types, inexpensive, fuel costs are typically lower disadvantages - material has a short light span (especially from UV light), condensation may build up on inside surface (diseases and reduced sunlight)

water

analyze water quality - key to efficient greenhouse operation

how to reduce light intensity to reduce heat

applying shading compounds or installing shading fabric (used only during spring and summer months when light levels are high and must be washed off for fall and winter)

light quantity

background info

irrigation practices

background info - 90-98% water, critical for high quality crops overwatering - one of the most common causes of injury to plants, creates oxygen deficit in root zone resulting in root rot under watering - typically grow slower, eventually wilt, decrease productivity important considerations when watering plants -timing (4 ways to determine when to water) - should be applied before signs of wilting, wilting indicates stress resulting in premature senescence 1. feeling weight of pot 2. feeling soil 3. using indicator plants 4. using tensiometers? -amount - thoroughly water each time, but don't over water -water carefully - apply to medium not foliage or flowers

inorganic fertilizer formulations

background info - both dry and liquid formulations used in greenhouses liquid fertilizers - can be applied as a constant feed (low concentrations each time plant is irrigated) like slow release, and is most popular, sustained growth and development disadvantage - shortly following application, slow decreases begin until next application (fluctuations in growth) dry formulations 1. fast release - immediately available 2. slow release - highly desirable nutrient analysis - levels should be monitored so plants aren't stressed

peat plugs

background info - consist of compressed peat moss that expands when moistened designed for growing plants for short periods of time advantages - transplanted directly without removing from moss medium, plugs come in different sizes, seedlings or cuttings can be planted mechanically

plant pests

background info - don't select site with numerous pests

ebb and flow

background info - form of sub irrigation that puns water into bench at regular intervals, filling benches with water and takes water via holes through bottom of pot, after enough water, they are drained advantages - flexible and easy to install, accommodates different pot sizes, plants easily rearranged disadvantages - more expensive

controlling greenhouse temperature

background info - good temp control is vital to maintain good quality crop, labor is most expensive cost three ways heat is lost from greenhouses 1. conduction 2.infiltration (through cracks or holes) 3. radiation (loss of heat from warm surface) three types of fuel commonly used 1. natural gas 2. fuel oil 3. coal (least commonly used) factors to consider when choosing a fuel source 1. availability 2. cost of delivery 3. transportation 4. storage 5. any special needs required by fuel

bedding plant containers

background info - grown in plastic cell packs, may be individual cells which vary in size, generally comes in sets of 2, 4, 6 or more, drainage hole in bottom advantages - facilitates transplanting, saves time and labor, reduces transplant shock disadvantages - plants may become root bound if let too long leading to transplanting shock

air pollution

background info - harmful or degrading material in air causes problems for nurseries ozone, sulfure dioxide, ethylene highly populated areas, pay close attention to nursery crops grown to avoid damage form pollution

temperature

background info - maintaining proper temperature is crucial can be simple or complex

green and flowering plant containers

background info - most are grown in plastic containers because less expensive, shape based on personal preference four types of pots (depends on growth habit of plant) 1. standard pots (equal in width and height, should not be used when growing tall plants they tip over easily) 2. azalea pots (slightly shorter, flowers, more stable) 3. bulb pans (half as high as width, used for propagating plants, also for shallow roots or plants grown from bulbs) 4. hanging baskets (made of wood, wire, ceramic or plastic, majority are plastic because they're lighter, proper size and drainage and saucers are important)

acrylic and polycarbonate coverings

background info - most popular rigid plastic materials, resemble glass panes advantages - lightweight and easy to install, require less support and are more adaptable (reduces shading), provide good light transmission and excellent heat insulation disadvantages - flammable, expensive

light

background info - must have adequate sunlight, artificial light not available plants vary in light requirements, so pick a place best for the type of plant you're working with need to be careful about street lights

bench orientation in the greenhouse

background info - plants are either grown in ground beds (on floor) or benches (raised) three common types of bench arrangements 1. longitudinal bench arrangement - beds run full length of greenhouse in several rows (fresh cut flower production) - easy mechanization but difficult access 2. cross benching - benches are arranged across width - easy access but less growing area 3.peninsula - one central aisle that runs long ways - easy access with maximum growing area

growing media

background info - produced to accommodate specific needs characteristics of good growing media - all mixtures should be reproducible and available, have basic physical, chemical and biological properties 1. good moisture and nutrient holding capacity 2. rapid water infiltration 3. aeration and drainage 4. decompose slowly 5. be free of toxins 6. have good cation exchange capacity and buffer capacity 7. provide good support

fiberglass - reinforced plastic coverings

background info - semi rigid greenhouse covering that can be bent, used on arched greenhouses advantages - allows same amount of sunlight through as glass, disperses light that makes intensity more uniform, easy to cool disadvantages - susceptible to UV light, dust, and pollution degradation, flammable (insurance costs higher)

glass coverings

background info - several grades and weights, depends on growers needs, advantages - best light transmission (90% of light), doesn't transmit light in UV range of light spectrum, UV light does not reduce transmission of light through glass disadvantages - expensive to contract, maintain and operate, has tendency to break easily, does not retain heat well

water

background info - should have dependable supply of good irrigation water which is low is salt, fluoride, chlorine and other contaminants cannot be completely dependent on rainfall need to know whats available from ground water, lakes, etc.

capillary mat system

background info - sub irrigation where pots are placed on mat saturated with water thats taken up by growing medium by wick action through holes on bottom of pot, mat must be placed on level surface advantages - flexible and easy to install, can readily accommodate afferent pot sizes, plants can be arranged disadvantages - has potential for algae growth

soaker hose method

background info - surface form of irrigation commonly used on flower beds series of hoses on surface of flower bed, water oozes or drips out of line

perimeter irrigation

background info - surface form of watering, pipes placed around perimeter of flower bed with water nozzles below foliage, equal amounts of water (foliage doesn't get wet) commonly used in cut flower industry (roses and carnations) where blemishes on flowers are not acceptable

soil texture, drainage and fertility

background info - texture, moisture, aeration, drainage required proportions need to be right two types of digging operations 1. ball and burlap 2. bare root

greenhouse coverings

background info - water and electrical lines should be placed, foundation level with good support, material must be strong, durable, easy to maintain and inexpensive, frame should also cast as little shadow as possible greenhouse covering - most important is to allow maximum amount of light in to greenhouse for growth and development of plants GPFA-P glass plastic film coverings fiberglass reinforced plastic coverings acrylic and polycarbonate coverings

overhead irrigation

background info - water applied over canopy of plants using spray nozzles, commonly used on bedding plants problem is wet foliage increases chances of disease watered in morning so they have enough time to dry

fertilization

background info -plants grown in greenhouse environment receive 100 times more fertilizer than those grown in field

Styrofoam pots

becoming more popular advantages - good insulator, lightweight, come in variety of sizes disadvantages - break easily, hard to clean

competition

before placing nursery, be aware of close nurseries competition should be minimized

ventilation and cooling systems (look at pictures)

benefits - renews supply of carbon dioxide needed for photosynthesis, circulates air which prevents diseases, prevents buildup of pollutants such as ethylene five main types of ventilation and cooling systems 1. natural ventilation system (air is exchanged through open range and side vents, one of oldest methods of cooling, chilling injury possible, screens are necessary to control pests) 2. fan-tube ventilation system (air distributed through plastic tubes with holes, used in conjunction with heating system) 3. fan and pad cooling system (creates summer cooling by drawing air through pads soaked with water, cools based on principle of evaporative cooling) 4. fog evaporative cooling system (uses fog generation system inside greenhouse, misting) 5. shading (spraying on white wash to reflect light and reduce light intensity) shade cloth - cloth used for shade when only certain parts of greenhouse need shading

headhouse

central building used for offices, storage, and workspace with attached greenhouses

materials used for formulating a good growing media

components - organic and inorganic, peat moss, wood, wood by products, bark, sand, perlite, vermiculite functions

negative DIF

day temp is lower than night temp

organic fertilizer

definition - naturally occurring nutrient materials derived from plants and animals examples - bone meal, blood meal, manures who uses organic fertilizers - typically used by specialty growers or hobbyists disadvantages - not used in greenhouses for a variety of reasons, not easily adapted to automated watering systems, produce volatiles (unpleasant in small environment because of odors and adverse effects)

inorganic fertilizers

definition - synthetic nutrient compounds derived from mineral salts background info - dry and liquid used in greenhouses, liquid more common because they can be applied readily with water advantages - convenient to apply and applied easily with variety of methods, can be applied in exact amounts needed

labor

dependable supply of skilled and non skilled is essential small permanent staff is necessary for nursery operations, yet seasonal labor pool should be available for specific occasions

utilities and services

dependable telephone, waste removal facilities, electrical and power services and others are essential to everyday nursery work if power goes off, lots of problems

temperature

description of USDA plant hardiness map - identifies 11 zone by annual minimal temperature for each zone, and maximum temperatures (12 zones) what to do after checking the plant hardiness map - grower should talk to local extension people and local weather agencies to confirm selection

structural parts of a greenhouse

diagram structural components of an A-frame greenhouse

DIF

difference between day temp and night temp

transportation

either truck, rail, bus, airport is essential close, but not too close (pollution)

advantages of detached greenhouses

environmental control can be easily regulated and can be programmed to meet specific needs

detached (freestanding)

even span (most common - symmetrical roof) uneven span (asymmetrical roof, uneven) quonset arch (more commonly used than gothic because it is easier to install) gothic arch

peat pellets

explanation - made of compressed peat moss that expands when moistened to become small peat filled pots (saves space during storage) advantages - seedling or rooted cutting can be transplanted directly without removing from plant medium

rainfall

factors affected by the amount of rainfall at a given location - 1. type of nursey crops that can be grown (where rain is limiting, pick plants that are able to handle this) 2. high rainfall during critical times is an important issue to consider (soil can become saturated which doesn't allow machinery into field and delays production) 3. excessive rainfall can cause soil erosion

land cost and availability

farmland - best nursery spots, most cases though this land is not economically smart undeveloped land - may initially be inexpensive, but cost of developing is high rural areas - although land may be less expensive, transporting materials and products to and from could be costly

types of benches

fixed - produced from many materials, must be able to drain properly movable - allow grower to change bench arrangement as needed (container spaces use this more often), used with one central aisle

day-neutral

flower in response to genotype

short-day

flower when dark is longer than specified length

long-day

flower when dark is shorter than specified length

effect of light intensity on plant height

high light intensity promotes shorter plants

manual watering

hose watering method used for many years and is used for small scale watering

light duration

involves length of exposure to light in a 24 hour period (day and light routines)

economic factors

land cost and availability lavor transportation utilities and service competition

low versus high humidity

low places plant in distress high leads to increase in plant dieases

types of irrigation systems

manual watering automated watering systems

factors involved in locating a greenhouse range

market accessibility climactic conditions topography and drainage water and other utilities zoning regulations labor supply expansion

layout of the greenhouse range

maximize light minimize heat loss maximize accessibility to trucks, customers, employees

disadvantages of detached greenhouses

more land needed, increases costs

tube irrigation

most commonly used two types of tube systems 1. chapin - lead 2. stuppy - plastic only major difference is weight at end of each tube advantages - water directly applied to soil without splashing plants with soil water mixture, reduces spread of diseases, individual pots can be watered automatically at the correct amounts and at right frequency, maximized plant growth and development, enables grower to apply water soluble chemicals (fertilizers and pesticides) disadvantages - expensive and not flexible, pots on bench have to be uniform in size and tube must be inspected so there isn't salt build up

drainage

naturally well drained, or if necessary, artificial drainage poor drainage leads to problem with soil aeration which leads to diseases soil takes longer to warm up in spring and delays

advantages of connected greenhouses

overall cost is less workers and equipment can move through greenhouse quickly and easily without going outside less yea tis required because there are more inside walls less land is needed

peat pots and inorganic rooting containers

peat pots - biodegradable compressed peat moss pots, generally treated with fungicide and something else to aid in see germination advantages - transplanted directly (reduce transplant shock) transplanting plants grown in peat pots - no part of peat pot should be above soil surface (will dry out and plant will die) inorganic rooting containers - also made from inorganic materials such as plastic foam (compressed plastic in form of cube or block)

air

photosynthesis - series of chemical reactions in which carbon dioxide and water are converted in the presence of light to carbohydrates and oxygen carbon dioxide in the atmosphere - found in low concentrations carbon dioxide in greenhouses - typically not limiting, during winter months when vents are closed, they can become limited, less photosynthesis, less crop yields unwanted gases in greenhouses - can be avoided by properly checking heating systems, possibly air purification systems

thermotropism

plants response to temperature

greenhouse integrated pest management (IPM) PREVENTION

prevent pest entry (easier than in the field) - screens on fence, disinfect shoes and have workers change into clean overalls before going into greenhouse weed control - remove weeds from inside and outside of greenhouse, use only chemicals approved for greenhouses sanitation practices - root rot, damping off, blite, powdery mildew (sanitation minimizes disease), dead leaves, flowers and stems should be removed crop inspection - daily inspection is very important to prevent spread of insects and disease, if one is found, make sure to discard it and implement a form oc control environmental manipulation - adjust to make unfavorable for pests biological (works well unless population of pests gets too high), genetic, cultural, mechanical, and chemical control otherwise a combination of them should be used

wind

problems associated with wind 1. areas with high winds can cause nursery plants to fall over and result in damage 2. soil erosion can be a problem (especially when high in sand) 3. interference with important nursery operations such as spraying how to overcome problems caused by high winds - nursery shouldn't be located where natural windbreaks are present, or where artificial windbreaks can be installed

nursery site selection

proper location very important environmental factors economic factors

connected

ridge-and-furrow barrel-vault sawtooth

types of containers

rooting containers bedding plant containers green and flowering plant containers

freestanding greenhouse

separate from other greenhouses

connected greenhouses

several or more greenhouses joined together

criteria for selecting containers

size (number one consideration) cost drainage durability ease of handling color shape