Light Lights are used to increase light duration and quality

Energy Processes Photosynthesis (6C H light = C 6 H H 2 0) Gas water red+blue = sugar gas water Respiration [C 6 H = 6C H Energy (36ATP)]

Components of Light Photoperiod Short-day plants flower when the day length is shorter than a critical number of hours. Chrysanthemums and poinsettias are both short- day plants. Long-day plants flower only if the day length is longer than a critical number of hours. Examples of long-day plants are tuberous rooted begonias, feverfew, and spinach.

Photoperiod Day-neutral plants, or indeterminant plants, are those plants for which the day length does not influence flowering directly. For these plants, the day length must be long enough for sufficient photosynthesis to occur to support growth. African violets and roses are examples of day-neutral plants.

Photoperiodic Chart Chart illustrates the effects of light and dark periods on flower production in long- and short-day plants.

Phytochromes Phytochromes are proteins with a light- absorbing component. P r forms during the night and is converted to P fr in sunlight.

Light Spectrum (350 to 700 nm) Chlorophylls absorb blue and red waves best and transmit green. Other pigments include carotenoids, phycoerythrins and phycocyanins

Light Quality Light quality refers to the type of light wave used by a plant. Red light - seed germination Far Red light - inhibits germination; promotes bulb formation in onions. Blue light - In vitro bud formation in tomatoes

Light Range (Foot-Candles) Light intensitylux foot-candles Low light538 – 10, ,000 Medium light10,760 – 32,2801,000 – 3,000 Hight light32,280 – 86,0803,000 – 8,000

Artificial Light Fluorescent Light provides and supplements light for plant growth and development.

Artificial Lamps Levels of light intensity produced by two (150 watt) incandenscent and two (40 watt) fluorescent lamps.

Light Intensity Measurements Measurement Light Meter (Foot - Candles) Full Sun (10,000 f.c.) Heavy Overcast (300 f.c.) Indoor light (incandescent 50 to 500 f.c.) Source Sun light Artificial light Incandescent Fluorescent Plant Growth Light Metal Halide High-pressure sodium vapor lights

Shade Cloth Cloth is designed to reduce light intensity so plants will not be injuried. Structure is typically built on a north-south orientation.

Plant Location Plant Location effects light intensity

Propagation Components Plugs – small seedling plants Layers – plants produced asexually from layering such as air layering. Propagule – a plant structure used for regenerating plants, which can include cuttings, seeds, grafts, layers, tissue culture explants, and single cells. Microclimatic conditions – any environmental factors in the immediate vicinity of the propagule during propagation

Propagation Components Hardening Off – the stress adaptation process or acclimation that occurs as a propagule, such as a cutting, is gradually weaned from a high to a low relative humidity environment during rooting.

Temperature Control Temperature - How is it measured? Scales (Celcius, Fahrenheit) A. Sources of Heat 1. Forced Air Heating 2. Heating Cables 3. Sunlight B. Effect on Plants 1. Compensation Point 2. Seed Germination C. Temperature Control Cool Pads

Humidity A.What is Humidity? 1.Definition B.Transpiration 1.Gradient 2.Rate of Evapotranspiration C.Methods of Control 1.Pebble Tray 2.Humidifier 3 Controlled Chamber

Water A.Importance of Water 1.Structure a.Wilting Point 2.Photosythesis a.Cooling Effect 3.Transpiration a.Definition b.Evapotranspiration (ET) Rate 4.Translocation a.Movement of Foodstuff 5.Absorption a.Water b.Minerals and Salts

Water Methods of Watering 1.Indoor a.Kitchen Faucet b.Watering Can c.Submerging d.Subirrigation e.Hose f.Wick Irrigation 2.Outdoor a. Garden hose b.Nozzle c.Root Feed d.Soaker Hose e.Landscape Irrigation System f.Drip Irrigation 3.Greenhouse a.Mist System b.Drip Irrigation c.Filter System