Ed Rosenthal: Efficient Marijuana Cultivation Pt. II

January 24, 2017   

If you haven’t read Part I, you can read it here.

In part one we discussed that marijuana’s initiation of flowering is based on a critical period of uninterrupted darkness. 

The fact that marijuana can be induced to flower at any size can be used to increase its yield considerably.

Allowed to complete its natural cycle, the plant grows vegetatively for several months before it begins to flower. During that time it’s canopy spreads by growing linearly. By that I mean that the plant requires a bit of time to fill its canopy. Then the plant begins to flower. So, when considering time and energy per gram of product, the vegetative, pre-flowering growth time must be considered.

Any material harvested that was grown during the vegetative cycle is of secondary value, so as far as the cultivator is concerned, this is a non-productive time period.

Using light regime altering techniques you can increase the plants’ productivity incredibly. Let’s say you are growing plants on two foot centers. To get to flowering stage, that is, filling their appointed canopy space, requires three to five weeks. Then they are forced to flower.

A two sq. ft. plant fills a 17” canopy. If it were replaced with four to nine plants the vegetative cycle would be completed in a fraction of the time. With four, each plant would only have to fill a canopy of about 8” x 8” or  64 sq. in. That would take at most 10 days, saving a minimum of 20 days. Of course there would be more mother and cloning work, but that cost is a fraction of the time, energy and labor saved.

Some varieties don’t grow very much after they are forced to flower. They can be placed radically closer together. Nine plants fit into 5” containers or spacing in that 17” square tray. These plants only stay in vegetation for three or four days before the light regimen is changed to force flowering. Each plant will produce only one main bud and will require little manicuring.

Plants can be grown in containers using planting mix or coir, but cultivators may find it more convenient to use hydroponic techniques and systems adapted to growing small plants. Growers can use Nutrient Flow (NFT), Ebb and Flow or drip emitters, and all of these systems and the parts to make them are available through GrowSpan.