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WHEN & HOW BLACK-OUT OR LIGHT DEPO Photoperiod Control Systems for Greenhouse Crops Daylength exerts profound effects on the growth and flowering of many plant species, and manipulation of daylength is essential for scheduling several greenhouse crops. The responses of plants to daylength may appear to be a perplexing subject, but it is easy to understand once some basic concepts are mastered. This article briefly reviews photoperiodism and photoperiod control systems for greenhouses. Photoperiod control is necessary for scheduling greenhouse crops such as mum, kalanchoe, Holiday cactus, and poinsettia. The latitude and species will determine whether shortening or lengthening of the daylength is needed. There are two types of photoperiod control systems used in commercial greenhouses: (1) using incandescent, fluorescent, or high-intensity discharge (HID) lamps during naturally short days (SD) to create artificial long days (LD); and (2) using opaque black cloth (or similar material) during naturally LD in order to create artificial SD. Shortening the daylength (artificial SD). Plants are covered with an opaque material that reduces the light intensity. To be effective, the light intensity must be decreased to less than 2 ft-c under the material. In most operations, plants are covered at 4-5 pm and shade is removed at 7-8 am to provide an 8-hour day. A 4’ height is recommended between the top of cloth and the bench (bed) top to reduce heat buildup around plants; tall crops (such as cut mums) require more height. The material must be placed over the plants continuously (every evening) until the response is maximal. Several types of materials can be used to cover plants, and include the following: (1) black sateen cloth is a jet black woven cloth made from cotton or a cotton/polyester blend, and costs ¯$3.50 per square yard; (2) polyolefin sheeting is a woven material that is tear-resistant and waterproof, and costs ¯$1.50 per square yard; and (3) 4-6 mil black/white plastic can be used but is not tear-resistant, and costs $0.27-0.41 per square yard. Tears and worn spots should be repaired, and overlaps of shading materials should be properly sealed to minimize light leakage. Occasional 24-hour skips in shading are not catastrophic, but flowering can be delayed. For mums, every day that shading is skipped delays flowering by one additional day. Failure to shade consistently may also cause irregular opening of flowers.	GREENHOUSE OPTIONS AND MODIFICATIONS Components & Black-Out (light depo) Options Our STARSTUCKTURE Gothic Arch Greenhouse Kits can be modified with solid end-walls or side walls to Make these designs more useful on farms for use as a utility structure as well as a durable greenhouse- With the addition available materials- this kit can become: 30 ft x 96 ft Model Roll-Up Side Wall Natural Venting Components These devices roll-up the side walls for ventilation. The Manual Hand Crank Model shown here is for regular roll-up sidewall installations. It rolls a tube that rolls up the sidewall material and this opens the sidewall. It rides up a tube and is braked so it cannot come loose and allow the side to fall down or come loose. This chain Driven model is used for opening high sidewalls. It can also be used for opening roofs Black-Out Frame and Components Black-Out Frames increase blooming and force flowering which is a neccary when growing for market and seasonal plant products. We recommend an "Interior Black-Out Frame for this purpose. We sell 24 volt, high torque roll-up motors (see below) for rolling black-out film, such as Panda Film or Mylar Film, on a timer to regulate photo-period andforce blooming- attached are a few designs that are easily built and installed inside our STARSTRUCKTURE Gothic Arch greenhouse kits. To print a copy of these kits just click on the following links: \| BLACK - OUT FRAME IMAGE 1 \| \| BLACK - OUT FRAME IMAGE 2 \| \| BLACK - OUT FRAME IMAGE 3 \| Most all of the components you need to build a Black-Out Frame are available near you at most Fence Supply Companies - Any Speciality Parts are Usually in Stock Here- including PANDA-FILM. FOR MORE INFORMATION CALL OR EMAIL US.
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WHEN & HOW BLACK-OUT OR LIGHT DEPO

Photoperiod Control Systems for Greenhouse Crops

Daylength exerts profound effects on the growth and flowering of many plant species, and manipulation of daylength is essential for scheduling several greenhouse crops. The responses of plants to daylength may appear to be a perplexing subject, but it is easy to understand once some basic concepts are mastered. This article briefly reviews photoperiodism and photoperiod control systems for greenhouses. Photoperiod control is necessary for scheduling greenhouse crops such as mum, kalanchoe, Holiday cactus, and poinsettia. The latitude and species will determine whether shortening or lengthening of the daylength is needed. There are two types of photoperiod control systems used in commercial greenhouses: (1) using incandescent, fluorescent, or high-intensity discharge (HID) lamps during naturally short days (SD) to create artificial long days (LD); and (2) using opaque black cloth (or similar material) during naturally LD in order to create artificial SD.
Shortening the daylength (artificial SD). Plants are covered with an opaque material that reduces the light intensity. To be effective, the light intensity must be decreased to less than 2 ft-c under the material. In most operations, plants are covered at 4-5 pm and shade is removed at 7-8 am to provide an 8-hour day. A 4’ height is recommended between the top of cloth and the bench (bed) top to reduce heat buildup around plants; tall crops (such as cut mums) require more height. The material must be placed over the plants continuously (every evening) until the response is maximal. Several types of materials can be used to cover plants, and include the following: (1) black sateen cloth is a jet black woven cloth made from cotton or a cotton/polyester blend, and costs ¯$3.50 per square yard; (2) polyolefin sheeting is a woven material that is tear-resistant and waterproof, and costs ¯$1.50 per square yard; and (3) 4-6 mil black/white plastic can be used but is not tear-resistant, and costs $0.27-0.41 per square yard. Tears and worn spots should be repaired, and overlaps of shading materials should be properly sealed to minimize light leakage. Occasional 24-hour skips in shading are not catastrophic, but flowering can be delayed. For mums, every day that shading is skipped delays flowering by one additional day. Failure to shade consistently may also cause irregular opening of flowers.