If you read my last post light Deprivation: Inro, then you have a basic idea of how a light dep system works and a few of the major advantages that come with it. It may sound like the ultimate investment, which it often is, however there are always pros and cons to just about everything, especially when it comes to greenhouse related products. This post is all about the pros and cons of a greenhouse light deprivation system when compared to outdoor cannabis cultivation.
Shorter Grow / Higher Potency / Added Control
In the plant’s early life they receive around 18 hours of sun light a day, which promotes the stem and leaf growth. When the plant is forced into a 12 hr on 12 hr off light dep cycle the plants begin to focus their efforts at forming their buds instead of growing their branches. Controlling the light supply forces the plant to start maturing, which it turn gives the grower the potential to cut their grow season down from roughly six months to around four months.
Depending on the time of year the grower decides to force flower their plants there is opportunity for higher potency. By forcing the plant to flower in a season when the sunlight is intense and abundant the plants will be forming their buds with high quality sunlight resulting in higher quality cannabis.
Further, lets not forget the huge benefit of having increased control over your crop. Light dep allows for the grower to strategically plan into when they want to harvest. This is huge, because in the competitive cannabis market timing can be very important. For example, if the market is dry and you’re sitting on a large supply, then you can get top dollar for you crop.
Added Responsibility / Smaller Plants / Humidity
Top on the cons list is the time dedication required for a successful light dep cycle. If you plan to manually lift a black out tarp over your greenhouse at the same time every day you are at risk of disrupting that 12 on 12 cycle. If for some reason this process gets screwed up the plants can get seriously damaged as they get shocked back into the vegetative state. A cure for this is automation, but that is another expense and device to power.
Shortening the growth-cycle in the vegetative state results in plants that are less developed and smaller harvest than what you could get with the long outdoor season. Another challenge is sustaining black out darkness while also getting proper air circulation. Usually exhaust and intake fans help control the temperature and humidity in the greenhouse by promoting fresh airflow, but in doing so they also let light in to the grow area. Circulation fans are often used during the black out period, but they only recirculate the stagnant air inside of the greenhouse. During the light dep period excess heat can build up, humidity levels can rise and the threat of mold becomes an issue.
In the video below, Kevin Jodrey owner of Wonderland Nursery brings up another potential con with light dep cultivation (00:33-1:45):
He says that they have been noticing that while deping a bunch of different varieties; supplemental lighting and blackout, they have been seeing 3-5% of indica based strains showing signs of hermaphroditism and incomplete flowering. If these plants were not exposed to a light dep cycle they would grow fine. His main point is that we have not had the chance to run through all of the strains with this production method so we haven’t been able to fully understand which strains are stable for these forms of manipulation and which aren’t.
Light deprivation is a risk, things can go seriously wrong if you manage to skip a day or two during the light dep process.Not to mention, your plants and yields will potentially be smaller than an outdoor grow, and mold might decide to take over in your dark humid greenhouse. However, the cons can be mitigated with some new accessories (breathable tarps, fan covers, automation, etc.), and in my opinion the pros far outweigh the cons. Where light dep lacks in size it makes up with speed, potency, and control. Just make sure to do some additional research into your specific operation to make sure a light dep system is a viable investment.
If you are interested in the first steps towards setting up your own light dep system then stay tuned for my next post Light Deprivation: Methods | Tarps | Suppliers
Do you have any experience with this topic? Any opinions on some additional pros and cons of light dep? Please share your thoughts in the comment section below.