SUICIEUDLE

Overhead system

plumbing over bench or bed

traits of an overhead misting system

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

in-bench

plumbing under substrate or along propagation bench/bed surface

in-bench misting system traits

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

Spacing of nozzles depends on:

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

Nozzles need head-to head coverage, what is this, and why is it important?

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

Line strainer

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

Deflection type nozzle

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

Mini sprinkler type nozzle

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

Static control system

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

Dynamic control system

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

Solenoid

electronically controlled valve to control water flow to the delivery system

Solenoid: Normally-open

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

Solenoid: Normally-closed

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

Solenoid: open VS. closed

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.

Centrifuge fogger

water ejected from spinning nozzle into cool airstream by fan

High-pressure fogger

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

Ultrasonic or pneumatic fogger

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

"True" Fog System

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

Transpiration (Ts) increases with what environmental factors?

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

Rooting for most crops best from ( X - X) degrees F?

70 to 81 degrees F

Main purpose for controlling environmental factors in propagation?

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

At what humidity does transpiration (TS) stop

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

factors to consider in choosing a greenhouse frame type?

Wind, snow-load, cost

Lean-to Greenhouse

usually placed in a south or eastern exposure

Gothic Arch

used in more northern areas (snow load)

Evan Span Gable

usually glass, acrylic or polycarbonate

Quonset or Hoop

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

furrow (gutter connected)

greenhouses constructed with connected gutters to each other

Hotbeds

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

Cold-frames

ground bed with no heat

Heat or sweat chamber

used in seed germination

Lathhouse

used for "hardening off"

Propagation frames have 2 main attributes:

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

Frame material types: Wood

- treated pine, redwood, cypress, and cedar

Frame material types: Metal

galvanized steel, aluminum (more common)

Frame material types: PVC Pipe

Greenhouse Covering Material: Glass

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

Greenhouse Covering Material: Polyethylene (poly)

(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

Greenhouse Covering Material: Acrylic (Plexiglass, Lucite, Exolite)

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

Greenhouse Covering Material: Polycarbonate (Lexan, Dynaglas, Polygal)

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

Greenhouse Covering Material: Fiberglass (resin reinforced fiberglass)

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

Bench System Cons

Expensive (more producers use floor production)

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

Bench System pros

~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

Greenhouse floor:

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

Floor Bed Systems:

(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

Controlling the propagation structure environment: Heating 2 factors to consider

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

Controlling the propagation structure environment: Heating, What methods are used for greenhouse heating

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

Controlling the propagation structure environment: Forced air heaters from combustion (natural gas, propane) require what for maximum efficiency

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

Controlling the propagation structure environment: Heating, Thermal Blankets

provides insulation
CSU uses shade cloth, has minor insulation effect

Controlling the propagation structure environment: Heating
one factor to consider that effects ALL structures

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

Controlling the propagation structure environment: Cooling, what are methods of cooling

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

Controlling the propagation structure environment: Cooling, Cons when using a sidewall for ventilation cooling

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

Controlling the propagation structure environment: Cooling, what happens when using exhaust fan and vent panel for ventilation (how does it move air)

Pushes air out of greenhouse

Controlling the propagation structure environment: Cooling, what factor impacts the cooling capacity of the Evaporative cooling system (fan and pad system)

the ambient or outside humidity

Controlling the propagation structure environment: Cooling, how does shading (cloth or paint) cool the greenhouse environment

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

When and where was container growing thought to have originated?

Egypt, Babylon and Greece (about 2500 years ago

What are the limited reserves in container gardening?

moisture, air and nutrients

Limited soil reserves have a large affect on what within the container substrate?

he moisture dynamic within the container substrate

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"

recognize interchangeable terms for "substrate"

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

Early container substrates were (X)based

mineral soil based (5% or less organic matter)

Cons with using Mineral Soil

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

when did container production become commonplace

1940's

1950's - University of California Los Angeles developed "UC Mix"- what did it consist of

50% peat:50% fine sand

1960's - Researchers at Cornell developed several mixes- what did it consist of

50% peat and 50% perlite or vermiculite

Mid to late 1960's -(X) became primary component of nursery substrates

Pine Bark

What are the 2 essential functions that container substrates provide?

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

Container Substrates Need to Be:

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

Substrate criteria: define Repeatable

Made up of components well adapted for plant growth and manageable

Substrate criteria: define Stable

doesn't easily break down

What 3 phases of matter does a substrate contain?

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

Solid phase : define "bulk density"

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

Bulk density depends on what?

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

Gas phase: define "air filled porosity"

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)

Substrate (fluid phase) Gas + Liquid:

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

Idea Range of substrate "Total Porosity"

%50 to %85 (production substrates)

Liquid phase: define "Volumetric Moisture Content"

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

Ideal Range of substrate "Air Filled Porosity"

%10-%30

Ideal Range of substrate "Volumetric Moisture Content"

%45-%65

"Liquid Phase" regarding containers is measured as "container capacity" or water holding capacity, what would you measure and how would you obtain this?

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

Perched water table

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

relating to water: define Cohesion

relating to the perched water table: what determines the height level of the water column of the perched water table?

PARTICLE SIZE IN THE SUBSTRATE

What particle size would allow for a higher perched water table? (smaller or larger)

Smaller, a finer substrate results in a higher water column

What does amending the principle-substrate mean?

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

Total porosity is comprised of: (X) and (X)

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

Ideal Total Porosity range:

(%45~%50)-%80

Ideal Air Filled Porosity range:

%10-%30

Ideal Volumetric Water Content or Water Holding Capacity range:

(greater than %40) %40 - %65

Substrate Solution

solutes dissolved in water and water within the substrate

What are the "solutes" dissolved in substrate solutions?

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

Cation Exchange Capacity (CEC)

Indication of how well substrate will hold positively charged ions

Higher Cation Exchange Capacity (CEC) typically produces what effect in substrate?

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

Higher CEC typically produces higher buffering capacities for nutrients, what does having a higher buffer capacity do?

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

Cation has what charge?

(+) positive

Anion has what charge?

(-)

Particles in substrate progressive have a more (X) as soil is broken down

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

CEC values (not necessary to know EXACT \#'s)

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!

define: PH

Concentration value of Hydrogen (Power of H)