SUICIEUDLE

plumbing over bench or bed

Easy to maintain and install ✓No risers or T's ✓Efficient use of space ✓Drip often a problem

plumbing under substrate or along propagation bench/bed surface

✓Risers usually 12 to 24" above crop ✓Harder to work on

1. Riser height 2. Nozzle type 3. Air movement in the structure or bed

head-to head coverage, water from one nozzle reaches all the way to the next nozzle. NO DRY AREAS

"Y" type most often used; clean regularly (more solutes = more cleaning)

stream of water strikes a flat surface upon leaving the nozzle producing the mist ✓Advantages - covers a larger area; operates at lower PSI (30 to 40 PSI) ✓ Disadvantage - coarse mist (larger water droplets

large water droplets; spinning action breaks up the water stream (too strong for germination stage, better for more established plants)

pre-set system using timers ✓24-hour clock - day-night ✓Cycling clock - how often and for how long

environmentally controlled Screen balance - weight (minerals, fungal, insects) so clean regularly ✓Electronic leaf - electrical circuit (dirt, minerals, fungus) ✓Thermostat - evaporation cools (optimum temperature?) ✓Photoelectric cells - light intensity and transpiration

electronically controlled valve to control water flow to the delivery system

water passes through when current is "off" (provides protection against power failure; need a manual gate valve) - always powered "ON" = more $$ electricity

open only when current is "on" (less expensive; needs a by-pass gate valve)

if we have a NORMALLY OPEN it takes power to constantly keep off, if power fails it will turn on, you need a manual gate valve to turn h20 on and off, NORMALLY CLOSED, needs gate valve bypass, goes around solenoid. if power fails, you need to manually turn on.

water ejected from spinning nozzle into cool airstream by fan

nozzle has very fine orifice; impact pin atomizes stream into droplets (type in Lab)

as water passes through nozzle it is atomized by high frequency sound wave or compressed air (think: household ultrasonic hummidifier)

Droplets remain airborne for evaporation (93 to 100 % RH) • Increase RH without over watering • RH controlled

✓Light (solar radiation) ✓Temperature ✓Wind ✓Relative humidity (RH)

70 to 81 degrees F

PREVENT DESSECATION! Key is keeping tissue turgid while propagule becomes self sufficient!

via misting/hummidity chambers, Ts stops when ambient RH is 100%

Wind, snow-load, cost

usually placed in a south or eastern exposure

used in more northern areas (snow load)

usually glass, acrylic or polycarbonate

very common in warmer climates; inexpensive; double wall poly if heated and/or cooled

greenhouses constructed with connected gutters to each other

ground bed with bottom heat (hot water, manure, etc.)

ground bed with no heat

used in seed germination

used for "hardening off"

maintains high RH, can be shaded but without a large structure

• treated pine, redwood, cypress, and cedar

galvanized steel, aluminum (more common)

expensive, heat loss high, heavy, permanent, high light transmission, low condensation (usually used more in "showcase" greenhouses, NOT seedling prop)

(common~%50 USA) about half of the greenhouses in the US; lightweight, inexpensive, retains heat well (double poly), lower light transmission, brittle in colder temperatures and with UV exposure, short life span (5 years max.), many colors available

excellent light transmission, excellent heat retention, weather resistant (hail?), can be treated for no drip (condensation), brittle in cold and with age, fairly expensive. BAD FOR HAIL

excellent light transmission, good heat retention, strong, light weight, low condensation, can yellow over time; can be double or triple walled.

CSU USES THIS. long-lasting, light weight, yellows quickly, burns readily(heaters lookout), brittle with age.

Expensive (more producers use floor production)

Benches on rollers can use up to 90% of floor space (75% is still good)

~Optimal~ -Raised (floor is coldest in greenhouse) -Built of decay and corrosion resistant material -Bench for easier sanitation and less disease -Can be fitted with bottom heat (winter cuttings and seed germination) -Benches preferred because of easy work height (30 to 36" high)

• 4' to 6' maximum width

Concrete is ideal for floor production but costly; can use flat carts more easily

Alternative is gravel with woven ground cloth and concrete walks, Harder to clean/disinfect BUT cheaper

(uncommon) -used in Netherlands Ground beds using organic substrates should be disinfested after each use Drainage a major concern! Floors need to be crowned to help drainage

Uniform temperature No harmful materials released into plant environment (ethylene)

Hot water distribution systems (natural gas, propane or alternative fuels) CSU HAS THIS Heater/boiler Heat pump Distribution in floor or under benches

Distribution fans (tube or HAF) Ventilation stack is needed to expel ethylene gas and other fumes

provides insulation CSU uses shade cloth, has minor insulation effect

side-wall height: Taller is easier to cool, but harder to heat; need thermal blanket or floor radiant heat height depends on external env. factors

Ventilation (sidewall) Ventilation (exhaust fan and vent panel) Evaporative cooling (fan and pad system) Shading (cloth or paint) whitewashing

Large open wall can allow pests, chemicals, foreign microbes, etc. to enter greenhouse

Pushes air out of greenhouse

the ambient or outside humidity

Reduction of light intensity and heat Cloth: uniform shade, exact degree of shade, light weight and easy to install Paint: uneven~ white paint reflects

Egypt, Babylon and Greece (about 2500 years ago

moisture, air and nutrients

he moisture dynamic within the container substrate

"the base on which an organism lives" in Agriculture: water (hydroponics), sand, soil, agar, etc. authors of our text define substrate as "the components that are used to fill the container and surround the roots"

"container medium," "potting medium," "container substrate" and "potting mix"

mineral soil based (5% or less organic matter)

In general, mineral soils alone are poor container substrates limited biological nutrients = lower soil microbiome activity= poor soil health water passes through, holds too much h20 in a container

1940's

50% peat:50% fine sand

50% peat and 50% perlite or vermiculite

Pine Bark

1)Reservoir of water, oxygen and essential mineral elements (nutrients)Anchorage

Repeatable Stable Sanitized, free of contaminates (pests, pathogens, etc.)

Made up of components well adapted for plant growth and manageable

doesn't easily break down

Gas(air), Solid (particles), Liquid (water)

Weight (dry) of substrate per unit volume of substrate particles

particle size distribution, particle density, and nesting of materials (gas/liquid content is predicated on bulk density substrate attributes)

ONLY AIR. space between (macro-pores) and within soil particles (micro-pores) Required for oxygen, respiration and root health. Water drains from these areas after irrigation (gravity)

total pore volume in substrate (air and water) Expressed as a percent of the total substrate volume at container capacity

%50 to %85 (production substrates)

volume of pore space in a substrate filled with water at container capacity (water holding capacity)

%10-%30

%45-%65

Maximum water held following irrigation and drainage due to gravity. (our substrate lab!)

water level in container, will exist at the bottom of the container, Capillary action holds water due to cohesion and adhesion

PARTICLE SIZE IN THE SUBSTRATE

Smaller, a finer substrate results in a higher water column

adding another ingredient to substrate (i.e. sand to pine bark increases bulk density and decreases total porosity and air space)

water holding capacity + total air space capacity (any space in substrate that is NOT occupied by solid matter)

(%45~%50)-%80

%10-%30

(greater than %40) %40 - %65

solutes dissolved in water and water within the substrate

Mineral ions Common gases: O2 and CO2 Organic compounds (bacteria, etc.)

Indication of how well substrate will hold positively charged ions

higher buffering capacities for nutrients [POSITIVE EFFECT: more efficient fert. uptake, less leaching via H2O washout]

Influences plants ability to uptake soil nutrients. Longer term nutrient supplementation = more efficient fert. uptake, less leaching via H2O washout VS low buffer capacity: too much nutrients without plants having ability to uptake nutrients

(+) positive

(-)

(-) Negative (ie: worm castings, compost)

aged pine bark 10.6, sphagnum peat moss 11.9, vermiculite 4.9, and sand 0.5 (think about how sand cannot be "composted" to further break-down VS. AGED pine bark.) the more negative ions a substrate contains, the higher CEC value is! (-) substrate can hold ALOT of (+) ions!

Concentration value of Hydrogen (Power of H)