The idea behind Light Deprivation is to get two harvests a year when growing outdoors. This can increase both bud quality and yields compared to having just one big harvest with monstrous plants.
This means completely covering or uncovering your plants, but with small enough plants you could also move your plants daily to hide them from the light
In essence, a blackout tent is used to artificially alter the plant’s light schedules (similar to how indoor growers put their lights on a timer), giving the grower the ability to force the plant to start making buds as soon as they are put outside!
Tips for Success at Light Deprivation
I’ve included the most actionable information from the article, as well as many extra tips and tactics I’ve learned from other outdoor pot farmers over the years! If you’re intrigued, make sure you check out future issues of this awesome publication!
Huge outdoor plants produce a lot of bud and are amazing to see, but are generally harder to care for and the huge colas are more likely to suffer from problems like pests and mold
Put auto-flowering marijuana plants outside when they’re about a month old
Give Extra Dark Hours in the Evening
Gorgeous pic by Wayne Elfering
Anything that already works as a greenhouse can usually be converted into an outdoor blackout tent by covering it with something that is light proof. However, be aware (and with greenhouses in general) that plants need access to lots of fresh air (and CO2) in order to grow quickly and also to prevent mold. Make sure they can still breathe!
If he had his druthers, he’d farm completely outdoors, sans light dep. “I’m convinced a completely outdoor run makes for a better high.”
Heavy or not, it’s constant. “Every day, someone has to be home to pull tarps,” said Turiel. She considers that to be the technique’s biggest drawback. “It absolutely ties you to the land.”
“People just love that indoor look,” said Gellman. “You can grow someone a big outdoor bud, and its potent, but it’s not purple or covered with powdered sugar.” Light dep cannabis gets closer to that frosty, indoor look, while still harnessing most of those sun grown qualities.
Example of a light dep greenhouse from Advancing Alternatives.
Farmers typically grow seedlings or clones under supplemental light to get a strong start, and then put them under light dep conditions to finish within two months. So long as they’ve got another batch of clones or seedlings ready to go into the ground, they can do it all again in time for fall.
Casali agrees. “You can’t miss a day,” he said. “Every morning, I’m up at 5:30am to make my coffee. By six, I’m pulling tarps. And then again, I have to be home in the evening to do it all again.”
The benefits of growing light deprivation cannabis
The process may or may not be super labor intensive. Gellman’s garden is small enough that the covering and uncovering of tarps doesn’t bother him. For Casali, the task is so big, he built a pulley system that lifts a 500-pound tarp up and over the plants. As for Turiel, it’s a lot easier when her husband—measuring 6’2” versus her 5’2”—pitches in. Otherwise, “it’s one person running back and forth to tie down sides before it flies off like a sail,” she said.
Light dep can also be hugely expensive for farmers. Unless they do their own cloning, it’s a whole lot of clones to purchase to put in the ground. Casali does all his own cloning, but if he didn’t, he estimates that each round of plants in his setup would cost $14,000. And farmers differ as to whether light dep yields more or less than a full-term run.
Growing autoflowers instead of photoperiodic cannabis allows you to have a lot of plants without having to worry about light dep, autoflowers don’t rely on a certain cycle to start flowering so if you want to have multiple harvests all year long, you may want to stick to autos.
Put the second batch outside and let them flower naturally, by now the light cycle should be the appropriate one for cannabis to flower so you won’t need to use the blackout tent unless it gets too cold or humid and you want to protect your plants from the harsh conditions.
If you prefer having to do this early in the morning, you will have to cover your plants before sunrise.
Obviously, when you are growing just once a year you have to wait a lot to be able to smoke your flowers, this technique makes it possible to harvest two times a year so you won’t run out of weed!
4. Maintaining the proper light cycle
To make this possible, growers often used automated greenhouses that can blackout their plants but there’s no need to buy expensive equipment, you can make your own blackout tent and enjoy the same benefits.
The light dep technique requires a lot of work, even though it’s cheaper than investing in an indoor grow setup, you will have to cover and uncover your plants every day and if something happens and you’re not home when you have to do it, you may end up ruining your harvest so autoflowers are a great way to avoid this and save you from lots of work.
As you may know, when growing cannabis outdoors there’s a growing season, this means that you will have to start and end your growing cycle according to the weather.
The structure used in light deprivation is basically a greenhouse that doesn’t allow sunlight to get in and is called a blackout tent, you can easily make this tent at home for cheap, just like a greenhouse, a blackout tent consists of a wooden or metal structure that can withstand the weight of a tarp.