If you’re spending a lot of money on premium greenhouse glazing in order to maximize light transmission or minimize heat gain, you’re likely wondering why you’d spend more just to cover it up. Light deprivation is mainly undertaken as a way to manipulate and control plant growth. Plants don’t count the days but rather react in development based on the conditions around them, including day length. Installing light deprivation equipment, such as auto retracting covers, could provide a combination of these benefits for your favorite greenhouse crop.
Flowering Control
The primary benefit of light deprivation is control over when and how long a plant flowers. Growers first began experimenting with light deprivation and other photoperiod controls in order to prepare bedding plants for specific seasons. Mums were among the first plants to undergo informal greenhouse trials to see how they react to light control. Poinsettias soon followed since they naturally change color right at or after the holiday season. Controlling the flowering cycle is essential for annuals especially because they begin to die-off and lose their luster a certain time after blooms begin. If plants flower too early in the greenhouse, they’ll look unappealing to customers or stop blooming by the time they’re planted. On the opposite end, plants that aren’t blooming when they go to retail outlets are unlikely to attract the attention of customers. Light deprivation is the grower’s main tool for manipulating flowering, so it occurs at just the right time for peak marketing.
Bud Formation
In addition to flower development, many ornamental and cut flower growers need to be concerned with bud formation control as well. Many plants, like St. John’s Wort, Baby’s Breath, and even common roses, are grown more for their unopened buds than their blooming flowers. In the cut flower industry, keeping plants at just the right stage for bud harvest is a challenge, even with advanced hormone and fertilization treatments. Light deprivation is essential, and is usually used in conjunction with short periods of day extension, to help trick the plant into budding without flowering.
Size and Height Development
Aside from bud and flower development, another main use of light dep is to control or manipulate plant size. Height development is particularly responsive to day length because many perennials change their habit dramatically when they think they’ve entered the second year of growth. Cycling a plant through an entire year’s worth of day length changes can accelerate its growth and development, allowing you to shorten the production time and cost for many plants. Instead of spending years in the field or greenhouse, everything from shrubs to bedding plants can be accelerated and ready to sell in just months.
Shortened Seasons
All of the benefits listed above are due to the ability to lengthen or shorten the natural season. Season manipulation is the key benefit of both light deprivation and artificial day extension. That’s why the two methods are commonly used together rather than separately. In the Northern hemisphere, days are the longest on June 21st and the shortest on December 21st. With the combination of light deprivation and artificial lighting, you could make it seem like December one week and June the next. Of course, most plants respond best to a more natural approach that mimics gradual changes. Some plants do need sudden shifts between long and short day lengths, but it’s all easy to accomplish with the right light deprivation covers from a company like BTL Liners.
Stronger Color
For poinsettias in particular, it’s not the plants blooming that is triggered with light deprivation. Rather, it’s actually a color change, in existing top leaves known as bracts. Other plants may flower just fine with normal seasonal light levels but produce less than ideal color. Short periods of light deprivation can bring out stronger color from many annual and perennial bedding plants alike. For example, Christmas cactus often bloom much more colorfully when triggered with a full light deprivation period rather than just gradual seasonal changes. With competition increasing annually in both the bedding and cut flower markets, increased color intensity could be the difference between success and failure.
Energy Savings
Aside from direct benefits to the greenhouse crops, some growers also choose light deprivation techniques in order to save energy. This is less likely when relying only on natural lighting since it’s free to use. If you’re using some or all artificial lighting, light deprivation periods reduce energy costs immediately. They’re also useful for controlling heat production when using inefficient lights; especially if you can vent air out without letting light in. The same light deprivation covers used for photoperiod control often double as thermal curtains, which have the potential to reduce total energy costs by 60% or more.
Of course, there are many more potential benefits from light deprivation depending on the plant or crop. Cutting-edge growers are constantly doing their own experiments with light blocking covers from BTL Liners. Order some materials today to build smaller tents or enclosures and you’ll know where to get the materials to expand
