by: Tevan Riedel
President, Americover, Inc.
Light dep techniques are gaining in popularity, especially among new cannabis growers looking to maximize yield and get the most out of their allotted plants. With new cannabis markets opening up and marijuana law reform paving the way for personal home cultivation, there’s never been a better time to supercharge your grow using only the power of the sun.
The idea behind light dep is that most cannabis plants will begin flowering when the days start getting shorter, peaking in late summer/early fall. By covering and uncovering your plants with a 100% blackout tarp, you can “trick” your cannabis plants into flowering earlier, delivering more harvests per season and increasing yield.
Here are some tips for growers to get the most out of their light dep grow.
1. CHOOSE THE RIGHT STRAIN
Use online research, word-of-mouth and advice from local growers to find strains that work well for light dep in your particular climate. Different strains have different needs and sensitivities, and timings. Knowing when to end the vegetative phase and trigger your plants’ flowering phase is one of the most important factors for maximizing yield.
If you’re just starting out, pick a strain that is resistant to mold, mildew, and pests. Pick one that can handle a little extra stress and variability.
2. STICK TO YOUR SCHEDULE
There’s no one schedule that is “correct” for light dep, but there are a few popular methods . Your exact schedule should depend on your location’s light, temperature, and humidity conditions, as well as your personal schedule.
The classic light dep schedule is 12 hours of light and 12 hours of dark, with the plants being covered at 7 p.m. and uncovered at 7 a.m. This schedule requires good ventilation, so some farmers choose to uncover their plants at night. Others simply cover in the morning before the sun comes up, uncovering a few hours later. A morning light dep schedule can reduce ventilation requirements but also requires commitment to rising early.
However, make sure that whatever schedule you pick, that you stick to it. Missing the timing of one covering may adversely affect your crop by interrupting flowering and even turning your plants hermaphroditic, which is a threat to your whole grow!
3. VENTILATION IS KEY
An evening light dep schedule will have you covering your plants in the evening while the sun is still up, so it’s important to have good ventilation inside your greenhouse during this period. Additional heat and humidity can stress out plants very quickly. Make sure you are constantly monitoring key indicators such as:
● Temperature ● Humidity
Different light dep schedules and climates have different ventilation requirements. If you don’t have a sufficient ventilation system to cool your plants, you’ll definitely need to uncover your plants at night, and may even want to consider a morning light dep schedule.
4. AVOID LIGHT LEAKS AT ALL COSTS
Just as it’s important to stick religiously to your schedule, it’s vital that your plants get uninterrupted dark for a full 12 hours, or the length of your dark phase. Light leaks caused by a poor fit or rips in your greenhouse cover will throw the flowering cycle out of whack.
Make sure your greenhouse cover fits well over the greenhouse. Look for a cover that is made specifically for light dep. Pick one that is strong, tear-resistant, and non-perforated, such as BOLD, which provides 100% blackout and is UV-resistant.
5. TRIM YOUR PLANTS
When it’s time to trigger flowering, you want to make sure your plant is as productive as possible. Large leaves that are blocking light to flowering sites are just dead weight when your goal is to produce high-quality flowers. During the vegetative phase, trim the plant to give more light to the flowering sites. With this extra growth removed, your plants will redirect their energy to the most important part of the plant: the buds. It is possible to overtrim your plants, though so make sure you read up on some trimming techniques .
6. GET HELP TO COVER/UNCOVER
With a standard 12-hour light dep schedule you could be covering and uncovering your plants up to 4 times a day. Before you begin depping, make sure you have a contingency plan for sticking to your schedule.
If you don’t want to go through the hassle of doing everything by hand, there are also automated systems that will cover and uncover your greenhouse mechanically at specific times. However, these systems can be expensive and break down. A less expensive option is to make manual covering and uncovering easier with equipment such as BOLD EZarm , which allow one person to easily cover/uncover within one minute.