Greenhouse Management 4 02 Understand greenhouse structures production

Greenhouse Management 4. 02 - Understand greenhouse structures, production and maintenance

Greenhouses ■ ■ ■ The “Greenhouse Effect”- collects and stores heat from the sun (radiant heat) Provides a protective environment to grow plants Many detached houses can be used as connected houses

GREENHOUSE STRUCTURES

Detached houses ■ Quonset ■ ■ Curved (half moon) roof bars Covered with plastic or fiberglass panels

Lean to ■ ■ ■ Roof slopes in one direction only Built against other greenhouses or buildings Generally faces south

Even span ■ ■ ■ Roof is equal in width and pitch on both sides Most commonly used as a single greenhouse Clear span, truss supports, no columns

Even span

Uneven span ■ ■ ■ One side of the roof is longer than the other side for southern exposure Usually found on hillsides with one wall May have a solid north wall

Uneven span

Detached houses-Advantages ■ ■ Easy to program and maintain temperature Easy to ventilate without exposing the plants to blasts of cold air

Detached house-disadvantages ■ ■ Requires more energy to heat and cool Higher initial cost

Connected Houses ■ Ridge and Furrow ■ ■ Even span structures placed one after the other No side walls

Barrel vault ■ ■ Quonset houses set on sidewalls Height of sidewall range from 7’-10’ depends on crops

Dutch-Venlo ■ ■ Ridge and furrow construction Highest percentage of light transmission

Saran-covered ■ ■ Used to reduce the intensity of bright sunlight in frost free areas Mainly used for florist crops

Connected houses-advantages ■ ■ ■ Require less land area Less construction materials Heat loss is less

Connected houses-disadvantages ■ ■ Snow build-up in connecting gutters Gutters shade parts of the greenhouse

Greenhouse Equipment and Controls ■ ■ ■ Heaters- gas or electric Thermostats-controls the temperature, should be at plant level Timers- for lights, shade cloth, irrigation, etc.

Greenhouse Equipment and Controls ■ Evaporative cooling systems ■ ■ ■ Most effective method for cooling a greenhouse Constructed of thick corrugated cardboard Reduces watering due to higher humidity created by evaporation from the dripping water in the cool pad

Greenhouse Equipment and Controls ■ ■ ■ Exhaust fans- pull hot air from the greenhouse Vents- located at the opposite end of the exhaust fan. Vents open to allow fresh air in the greenhouse Circulation fans- circulates air in the greenhouse even when the exhaust fan is not running. Provides a uniform temperature throughout greenhouse

Greenhouse Equipment and Controls ■ ■ Misting systems- cools the greenhouse and provides a fine mist for seeds and cuttings Overhead irrigation system- waters greenhouses or shade houses but may not give the deep watering some plants need Drip Irrigation- tubes with emitters go to individual pots for water. A very efficient way to water. Lights- provide additional lighting for plants on cloudy or wintery days. Black cloth will block light

Greenhouse coverings ■ Greenhouse film (polyethylene film) ■ ■ 3 -6 mil thick Standard to UV treated. UV film keeps Ultra Violet rays from damaging plants Inexpensive Long lasting and easy to replace

Greenhouses coverings ■ Acrylic panels ■ ■ ■ Energy efficient Impact resistant Available in a variety of widths and lengths

Greenhouses coverings ■ Polycarbonate panels ■ ■ Twin wall panels Corrugated panels Available in a variety of widths and lengths Relatively expensive

Greenhouses coverings ■ Solexx panels ■ ■ ■ Flexible Twin wall 3 -6 mil thick Opaque Relatively expensive

Greenhouse plant terms ■ ■ ■ Annual- plant that completes their life cycle in one year Biennial- plants that complete their life cycles in two years Perennial- plants that live more than two years

Greenhouse plant terms ■ Sow- to plant seeds ■ ■ Direct sowing- starting seeds directly into the soil or pots. No transplanting necessary Indirect sowing- starting seeds in flats, trays, etc. and transplanting them into the soil or other pots

Greenhouse plant terms ■ ■ ■ Media-soil Deadheading- removal of spent or dead flowers Pinch- removal of the top portion of a plant to make the plant more compact Full sun- at least 6 hours of sun each day Part shade- morning sun until 12: 00 noon, no afternoon sun Shade- a few hours of morning sun, filtered light or full shade

Bedding Plant Soils/Media ■ ■ ■ Vermiculite- expanded mica, sterile Perlite- expanded volcanic rock Peat moss- decomposing parts of sphagnum moss typically found deep in bogs Sand- finely ground stone Bark- tree bark usually shredded or ground Commercially prepared soil mixes contain peat moss, perlite and vermiculite and are sterile, weed, insect and disease free.

Containers ■ ■ Flat- plastic tray usually for planting seeds or holding cell pack (10”W x 20”Lx 2 1/2 “D) Cell pack- several small cell like pots of plastic molded together. Four common sizes are 804, 606, 1206 and 1801 Peat pots- insulate the roots, can be planted directly into the soil, breaks down when planted, roots grow through peat material Eco pots- expensive, made from plants and vegetable oil.

Containers ■ Jiffy 7 - compressed peat moss covered in a fine mesh. Expand when soaked in water and can be planted directly into the soil. Used for sowing seeds or rooting cuttings

Containers ■ Plastic pots ■ ■ ■ Standard pot is the same width and the top as it is high Azalea pot is ¾ as high as its top diameter or width Vary in sizes and shapes

Containers ■ Clay pots ■ ■ ■ Made of porous Can be glazed Various sizes and shapes

Containers ■ Hanging baskets ■ ■ ■ Plastic, wire, cloth pouches (living walls) Wire hanging baskets may require some type of liner Varies in sizes 8”, 10”, 12”, 16”, etc.

Greenhouse Production-Seeds ■ ■ Select seeds to sow. Read specific instructions for selected seeds. Sow selected seeds in a sterile seed starter media. Cover if necessary Water seeds from the bottom or mist Cover seeds with a humidity dome (if necessary)

Greenhouse Production-Seeds ■ ■ Place seed flat on the bench in the appropriate light and/or on propagation mats if needed Check seeds daily for moisture Once seeds germinate and true leaves appear (2 nd leaves), prepare to transplant Loosen media to prevent breaking roots and stems of seedlings

Greenhouse Production-Seeds ■ ■ ■ Hold plants by their leaves. Do not hold the stem as they bruise easily Transplant seedlings into saleable containers slightly deeper than it grew in the flat Water newly transplanted seedlings Provide appropriate light for plants Create a pest free environment and control as needed Harden off (drop the temperature and reduce water) before moving plants out to shade houses or protected areas

Greenhouse Production-Cuttings ■ ■ ■ Select plants for cuttings (English ivy, pothos, wandering jew, etc. ) Make cuts below the node (area on the stem where leaves grow), remove leaves (if necessary) dip in water and dip in rooting hormone, tap lightly Make hold in the sterile soil Stick cuttings into the hole Gently push soil around cuttings

Greenhouse Production-Cuttings ■ ■ Place under greenhouse benches for a couple of days to lessen shock Grow in a sunny location in the greenhouse

BEDDING PLANT PROBLEMS

Cultural disorders ■ Seed germination problems ■ ■ ■ Improper temperatures Over watering or under watering Chemical residues in soil Seed planting depth Low quality seeds

Cultural disorders ■ Seed germination solutions ■ ■ Maintaining proper temperatures Maintain proper moisture levels Chemical free soil plant at proper depth Use high quality seeds

Cultural disorders ■ ■ Fertilization problems ■ Lack of nutrients ■ Root injury ■ Improper p. H in soil ■ Excessive fertilization Fertilization solutions ■ Testing soil ■ Applying correct amount and kinds of nutrients ■ Correct p. H

Cultural disorders ■ Uneven growth problems ■ ■ ■ Poor mixing of soil Uneven moisture levels Unlevel flats Uneven bottom heat Poor grading of seedlings

Cultural disorders ■ Uneven growth solutions ■ ■ ■ Properly mixing soil Even watering Placing flats level Replace damaged propagation mats or cables Grading seedlings by size

Cultural disorders ■ Tall and spindly growth problems ■ ■ ■ Too much nitrogen fertilizer Overwatering low light intensity High temperatures

Cultural disorders ■ Tall and spindly growth solutions ■ ■ ■ Use the correct amount of nitrogen Reduce frequency of watering Lower temperature Provide more light Use a growth retardant such as B-Nine

Diseases ■ ■ Disease problems ■ Damping off- seedling fall over causing the stem to rot ■ Botrytis- lower leaves are brown, rotting and drying out Solutions ■ Use sterilized soil ■ Use fungicides to control diseases ■ Improve air circulation ■ Increase air temperature around plants

Pests ■ Pest problems ■ Plants or seedling missing caused by slugs, snails or roaches

Pests- Pest Problems ■ Holes in the leaves damaged leaves or missing parts ■ ■ Aphids- green soft bodied, winged or non-winged, sucking insect Mealybugs- white cottony, sucking insects Spider mites- red body pest with eight legs Scale- brown, hard shelled sucking insect

Pest Problems (cont. ) ■ ■ Thrip- small translucent, sucking insect Whiteflies- powdery insects with four white wings, sucking insect Fungus gnats- thrive in moist wet environments, larba feed on plant roots and new callused tissue Leaf miner- larva produces mines by burrowing and feeding between the upper and lower epidermis. This allows air in and changes the leaf color in the mines to pale green or silver

Pest Problems (cont. ) ■ ■ ■ Cutworms- can enter the greenhouse as moths and lay eggs. Cutworms chew stems at the soil level Slugs- 2 -3” slimy brown body, burrowing pests, damaging roots and leaves of plants Caterpillars- eat plant parts, chewing insects

Pests

Pests ■ Pest solutions ■ ■ Monitor plants on a regular basis for insect problems Identify pest Use beneficial insects- parasitic wasps, ladybeetles, praying mantis, lacewings, or use an insecticide Set up a pesticide program. Use pesticides if necessary.

Pests ■ Pest solutions ■ ■ ■ Aphids- ladybeetles, praying mantis, insecticidal soap Mealybugs- insecticidal soap Spider mites- predatory mites, miticide Scale- outdoor use dormant oil, greenhouse alcohol on individual insects or insecticidal soap Thrip- parasitic wasps, insecticidal soap

Pests ■ Pest solutions ■ ■ ■ Whitefly- whitefly trap (sticky board), insecticidal soap Fungus gnat- watch moisture levels in the greenhouse, biological control such as Bacillus thuringiensis (Bt) Leaf miner- pyrethroid (attacks the exoskeleton of insect) Cutworm- Bt Slugs- traps, handpick Caterpillar-Bt

GREENHOUSE MAINTENANCE

Structure ■ ■ ■ Painting (wooden (rot) and metal (rust) structures) as needed Flooring (gravel, wood, cracked concrete) replace as needed Doors (steel, wood, metal) repair as needed

Replace covering ■ ■ Glass replace when cracked or broken Fiberglass replace when damaged Greenhouse film (polyethylene film) replace when torn or damaged Shade cloth- cover or take off depending on season

Equipment repair ■ ■ Heater- motor, fan blades, gas/electric lines, etc. Ventilation system- belts, motor, etc. Irrigation- clogged emitters, holes in tubing Lighting- electrical, bulbs

Pest Control ■ Weeds, Insects, Diseases- set up a maintenance schedule

PLANT MAINTENANCE

Plant maintenance ■ ■ ■ Water plants regularly, avoid watering in the middle of the day during the summer Set up a fertilizer schedule Check for insects and diseases and treat appropriately Control weeds Pinch plants to encourage fullness if necessary Keep the greenhouse clean