Horticultural light deprivation is the practice of physically excluding light from reaching a crop in production. Inside of grow rooms in warehouses, this practice is as simple as turning off the lights. Bringing this practice to the greenhouse environment, however, requires some additional equipment. Black cloth, blackout cloth, or light deprivation systems can be deployed to a single bench or across an entire greenhouse.
When should light deprivation systems be used?
Use of a light deprivation system, aka blackout or black cloth, allows for a crop to be produced under short-day conditions year-round, regardless of ambient conditions. Effective light deprivation results in completeblackout under curtains, as even as little as 10 µmol of light can be enough to trigger photoperiodic responses in some crop species. Black out systems are necessary for year-round greenhouse production of crops that require a short-day period in their production cycle. Even if the natural daylength is shorter than the critical photoperiod for a crop, blackout systems provide an extra layer of protection from light pollution due to parking lots and streetlights. For urban and suburban locations, it’s good insurance.
Light deprivation systems can also make you a good neighbor if you are lighting your production space into the night at any time of the year. Some municipalities are instituting rules around light pollution, making black out systems an important part of your business plan.
What crops benefit from light deprivation systems?
Cannabis and Hemp – Cannabis and hemp require a critical photoperiod of less than 13 hours to initiate and continue flowering. Cannabis growers produce vegetative plants and maintain mother/stock plants under long photoperiods and “flip” to short photoperiods when ready to flower. For year-round cultivation, light deprivation systems are critical in the greenhouse environment during the summer. One consideration for summer production is climate control under the black cloth. Remember that fans will still need to run, so be sure to install a light deprivation system on your exhaust fans, too. By managing the climate and the photoperiod, growers can produce high-quality short-day crops in summer.
Ornamental flowers – Some ornamental flowers require short photoperiods for flower, while others require long photoperiods. Poinsettias, mum, petunias, and tuberous begonias are just a few of the crops with special lighting requirements under normal production cycles. Black out cloth can serve to either suppress or initiate flower, depending on variety chosen.
Are you looking to retrofit your greenhouse space with a light deprivation system? Are you are planning a new structure and want to include a black out system? Either way, ask your Griffin sales rep about light dep systems from Advancing Alternatives. These systems can be installed externally or internally on freestanding greenhouses to keep light out or keep light in. Robust and automated, a system from Advancing Alternatives will provide trouble free service for many years. Click here to request a quote.