Green House Lighting Shannon Lawrence HORT 6050

What is Light? -Light is electromagnetic radiation that has a wavelength between 4,000 (violet) to about 7,700 (red) angstroms -Utilized by plants during photosynthesis - Measured in Lumens and Foot Candles (for our purposes)

Lumens It is the basic unit of light Describes the total amount of light present

Foot Candle Basic unit of light intensity Measured in Square Feet One lumen per sq.ft. = 1 foot candle (500 lumens per sq.ft. = 500 fc)

How Much Light to Expect Average lit room is about 7 foot candles Average lit room is about 7 foot candles Summer days can be close to 12,000 Foot Candles Summer days can be close to 12,000 Foot Candles Cloudy days can vary from around 1,000 to below 300 Foot Candles Cloudy days can vary from around 1,000 to below 300 Foot Candles Full Moon Light-.02 Foot Candles Full Moon Light-.02 Foot Candles Starlight Starlight

Why Light is important? When light is absorbed by a plant leaf, it is used as the main energy source to start extremely important processes such as photosynthesis (Light, CO2, and Water) It also aids in the maintaining of homeostasis. mportance_of_light.shtml mportance_of_light.shtml

How the Sunlight Effects Plant Growth nm UVC ultraviolet range which is extremely harmful to plants because it is highly toxic nm Includes harmful UVB ultraviolet light which causes plants colors to fade nm Range of UVA ultraviolet light which is neither harmful nor beneficial to plant growth nm Start of visible light spectrum. Process of chlorophyll absorption begins nm Peak absorption by chlorophyll occurs, and a strong influence on photosynthesis. (promotes vegetative growth) nm green, yellow, and orange bands - less absorption by pigments nm red band. Large absorption by chlorophyll occurs, most significant influence on photosynthesis. (promotes flowering and budding) nm There is little absorption by chlorophyll here. Flowering and germination is influenced nm Totally infrared range. All energy absorbed at this point is converted to heat.

Determine Your Lighting Needs! Know Know what the requirements are for your crop Know Know the type of weather you have look If beginning in a new area, look at old weather data to determine the number of cloudy days for years past.

What are the options? Natural … you get it whether you like it or not! Artificial …like a Loan Shark… you may need one, but its gonna cost you. Shading … A good dark side???

Natural Lighting Cheap source of lighting and is the first choice for most growers usually! In the South, sunlight is usually not a problem… usually! with labor and or investment) Intensity Can Be Controlled (with labor and or investment) Helps warm a greenhouse during winter. It is what most plants are accustomed to.

Negative Aspects of Natural Lighting Uncontrollable- We must accept what nature gives us. (Cloudy, dark) Not all plants are sun lovers and can tolerate full sun- African Violets (only about 1000 fc)

Artificial Lighting

Artificial Light Enables a grower to extend the growing day Can be used for night breaks on plants(shortens day length) Can be utilized on cloudy days, so plants can perform better Can provide red light or blue light RedBlue Red for flowering/Blue for Vegatative

Not So Good Things About Artificial Light Initial Cost is sometimes extreme Your greenhouse may need upgrades (electrical, support for lights, rearrangement, etc) Use electricity Electricity may not always be available (Thunderstorms in the South) $$$$$$$$ All add up to $$$$$$$$

What are the options?

What are the Options?

What are the options? Metal Halide Lighting Comparison WattageLumens/WattTotal LumensLight Intensity (in foot candles) , , , ,

What are the options? Sodium Vapor Lighting Comparison WattageLumens/WattTotal LumensLight Intensity (in foot candles) , , , , ,

COST Around $2.65ft² for High Intensity Discharge (light wattage / 1000) x electricity cost per kilowatt hour = Operating cost per hr operating cost per hour x hours used per month = Operating cost per month

HID Light Output Primary Growing Area Supplemental Growing Area 100 watts2' x 2' 3' x 3' 250 watts3' x 3' 5' x 5' 400 watts5' x 5' 8' x 8' 600 watts6' x 6' 10' x 10' 1000 watts8' x 8'12' x 12'

Unifier 400 MH (36,000 lumens) $215 Price: $215 Unifier 1000 MH (110,000 lumens) $255 Price: $255 Unifier 400 HPS (50,000 lumens) $229 Price: $229 Unifier 1000 HPS (140,000 lumens) $319 Price: $ x75 GH=2250ft²: 2250/ 144= or w HPS lights $5104$ x $319= $5104/2250= $2.27 ft² for a good supplemental light system (Initial Cost)

Shade

Benefits and Drawbacks Can be used to keep plants from burning up Can be used to lower the temperature of greenhouse Can grow certain plants outside in a shade house (Low overhead) Pulling shade can be labor intensive $$$$ Can be automated Sometimes it is unwanted (Too much Superstructure)

A Few Recommendations By A Supplier 30%30% Chrysanthemums, Asters, Snapdragons, Geraniums - 30% Chrysanthemums, Asters, Snapdragons, Geraniums 30% - 47% Various Vegetables & Herbs, Iris, Lilies, Gloxinias, Misc. Bedding Plants - 47% Various Vegetables & Herbs, Iris, Lilies, Gloxinias, Misc. Bedding Plants 47% - 55% Bromeliads, Ficus, Orchids - 55% Bromeliads, Ficus, Orchids 55% - 63% Orchids – - 63% Orchids – 63% 73% Ferns, Philodendron, Orchids 73% Ferns, Philodendron, Orchids 73% - 78% Ginseng (Special lath weave fabric for ginseng growers) - 78% Ginseng (Special lath weave fabric for ginseng growers) 78% - 80% Similar to 73% - 80% Similar to 73% 80% - 92% Aglaonema (Chinese Evergreen) - 92% Aglaonema (Chinese Evergreen) 92%

Cost of Shade 30% $.13sq/ft 30% $.13sq/ft 40% $.15sq/ft 40% $.15sq/ft 50% $.16sq/ft 50% $.16sq/ft 60% $.18sq/ft 60% $.18sq/ft 70% $.20sq/ft 70% $.20sq/ft 80% $.24sq/ft 80% $.24sq/ft 90% $.25sq/ft

What is right for you? Evaluate your crop lighting needs Determine if you are in a low/medium/high light intensity grower Weigh the costs- can extra expenses be justified?