Ed Rosenthal
Pro tips on increasing MJ yield
"Marijuana has two main stages of growth: vegetative and flowering. Most varieties are “short-day plants” (sdp), and their stage of growth is determined by the number of hours of uninterrupted darkness the plants receive. Most varieties respond to a critical dark period (cdp) of at least 10.5 hours by initiating flowering. Other popular sdp’s are chrysanthemums and poinsettias."
"Using techniques based on cdp, growers can easily manipulate plants to grow vegetatively or to flower at any time of the year in a grow room, greenhouse or outdoors, weather permitting. Growers can use this to their advantage in many ways." Some examples:
"Plants can be started early in the season and be kept growing vegetatively by interrupting the dark cycle several times daily using fluorescent, HPS, or red LEDs."
"Plants can be forced to flower early in the summer rather than in the fall using light deprivation. Growers usually use a regimen of 12-12 light-darkness. Three advantages to this, (1) The buds receive more light when maturing in the summer rather than the fall so they grow bigger and have a higher quality, and (2) growers can beat the others to market, when prices are still high. (3) Plants can be manipulated to grow to the size you find most convenient."
"When marijuana is forced to flower and ripen early several problems that often plague gardens are avoided. Buds that are initiated and ripen in summer are exposed to more light than autumn flowers, so they grow larger and more potent. Summer grown flowers aren’t affected as much by “weather”.
"Another advantage for greenhouse growers and cultivators in the southern and mid-tier states is that they can use light deprivation techniques to produce two to four crops per year."
"GrowSpan makes it easy for you with its fully automated light deprivation greenhouses. A less expensive, but equally effective, method is to use row cover framing and white/black film to manually control light. With the light deprivation greenhouse, repeating timers are used in the system to break up the dark periods keeping plants from getting too long a 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 its 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."
For more information:
GrowSpan Greenhouse Structures
1395 John Fitch Blvd
South Windsor, Connecticut 06074
Toll-free USA: (800) 476 9715
International: +1 860 528 9550
info@growspan.com
www.growspan.com