Cannabis growers know darkness is as important as light. You may not think of the principles of yin (dark) and yang (light) when planning your light deprivation schedule, but savvy growers understand the dual needs of cannabis. And whether your greenhouse sits in the Pacific Northwest under long summer days or in the hotter climes of the Central Valley, it’s essential to balance darkness and light for a maximum bud harvest.
Why Darkness is Important for Cannabis Plants?
Cannabis is a photoperiodic plant that responds to seasonal changes in light. That means when the days grow shorter, the plant’s life cycle is nearing its end, and flowering occurs for reproduction. In nature, male cannabis sacs release pollen to pollinate female plants in blossom. The result is seeds, which allow the plant to produce the next generation.
As a cultivated plant, cannabis still responds to light changes. Depending upon the strain you’re working with as well as your environmental demands, your light-to-dark ratio will vary a bit. If you’re new to the strain (or growing), talk to old hands about when to end the vegetative phase and trigger your plants’ flowering phase. That timing is critical to maximizing your yield.
How Much Darkness is Needed?
Light deprivation is ideal for producing high-quality crops. A light-deprivation system helps to control exactly how much light is exposed and reap many benefits. Below are the we discuss how much darkness is needed at each stage of growth.
The Vegetative Stage of Cannabis
Cannabis in the vegetative stage (when it is growing at a rapid pace) needs at least 13 hours of light per day. In fact, indoor growers commonly use an 18/6 light to dark ratio to encourage faster growth. (Note that most indoor growers vegetate their plants 4 – 8 weeks.)
The Flowering Stage of Cannabis
When you are ready for your cannabis plants to flower, a 12-hours of light and 12-hours of darkness schedule is standard. Nighttime provides darkness, keeping cannabis on somewhat of a natural clock. This is why indoor growers need to make a deliberate effort to not only create long, bright days but also emulate dark cycles for cannabis to grow large full buds.
Keep to Your Chosen Schedule
If you decide on the classic 12/12 light dep schedule where you cover your plants at 7 p.m. and uncover them at 7 a.m., be consistent with that schedule. Keep in mind that this schedule requires adequate ventilation, so some growers will choose to uncover their plants at night once the sky is completely dark.
What many growers don’t realize is that cannabis demands an uninterrupted dark cycle. Just as your good REM sleep would be interrupted if a light popped on at 2 a.m., cannabis doesn’t fare well when any light disturbs it during its dark “sleep” cycle. The moon and stars don’t bother cannabis, but any artificial light can stop its bud growth. In fact, light interrupting its dark cycles can make cannabis so stressed and irritable that it can lead to hermaphroditism. That can pollinate females and ruin your plants.
Is there a Way to Simplify Light Deprivation?
Covering and uncovering your greenhouse on a set schedule, day in and day out can be extremely time and labor intensive. Pulling tarps is a lot of work, but using the right tools and products makes all the difference. To improve your harvest, you need to provide ample, reliable darkness for your cannabis, a good light deprivation cover and a tarp puller system will help you maintain your light deprivation schedule.
Americover’s BOLD® Black Out Light Deprivation Tarp is the top-selling greenhouse cover of its kind nationwide, consisting of two sheets of high-strength virgin polyethylene film laminated together with a third layer of molten polyethylene. The cover is scrim reinforced for superior tear resistance.
Plus, the cover can be easily set or lifted with the BOLD® EZarm Tarp Puller. The BOLD® EZarm allows one person to easily cover and uncover a greenhouse without additional help, making light deprivation so much easier.