My marijuana seedlings have been growing in a wick system for about 6 weeks. Three of the female plants are over a foot tall and have extensive leafy growth. When should I start flowering them? If I start forcing now, would my mature flowers suffer later on?
It really all depends on the strain of marijuana and how big you want the ripened plant to be. As soon as you switch from a vegetative light schedule (18 to 24 hours per day) to a flowering light schedule (12 hours of light, 12 of darkness), the plant starts to shift into flowering. Marijuana strains that have mostly indica characteristics will grow another 25 to 50% after the light regimen changes.
Marijuana seed companies frequently sell seeds that are indica-dominant hybrids. They tend to best as medium-sized plants that make it to 2 or 3 feet in height with a canopy that ranges from 1 to 3 square feet. These can be used in a sea of green set-up if need be. Plants of this variety are usually forced to flower when they are 12 inches tall and will achieve heights of between 15 and 24 inches at ripening. Each marijuana plant will have a canopy the ranges from 0.25 square feet (6” x 6”) to 1 square foot (12” x 12”).
By contrast, sativas and sativa-dominant hybrids tend to stay in vegetative growth for some time. Certain pure sativas grow to around 3 to 5 feet even if they are forced to flower at 12 inches. Some of these sativas don’t respond to the 12/12 light regimen because they are native to the equator where light and darkness are around 12 hours every day of the year.
Thus, the plants must use other indications to begin flowering. While other environmental factors might play a role, the size of the marijuana plant and its age also help determine whether it will go into flowering. In this state, pure sativas can flower for as long as four months (or more). Flowers will appear during vegetative growth and the plant will put more energy into reproduction.
Sativa plants native to the 20th parallel have more light sensitivity than equatorial plants, but they will still growing even in flowering stage. Land-races from Jamaica, southern Mexico, Thailand, and Vietnam all make it into this category.
Sativa/indica hybrids sold commercially are sensitive to light and will usually mature from the middle to the later periods of the season. If you’re growing marijuana indoors, you should give them enough room to spread out—at least 2 square feet (18” x 18”) of canopy for each plant. They should also have at least 4 feet of space going upwards. They will not perform well using sea of green methods.
Both hybrid sativas and hybrid indicas can be forced to flower no matter what size they are. Bud quality is neither dependent on nor influenced by plant size. Buds that mature on two clones from the exact same mother plant—one freshly planted and the other having grown in vegetative state for three months—will show no variance in the quality of the buds.
In the end, it’s all up to you. Decide how big you want the marijuana plant to be when it is finished flowering. Plants that are small at flowering will still be small at ripening. You should also be aware of a few things before you make your decision. For instance, if you get caught, federal law only charges you by the amount of plants that you have (not the size). So, you could technically face the same charge for 6-foot behemoth as you would for a tiny seedling.
In addition, the sea of green technique allows you to grow marijuana crops faster because each plant has to grow only a small amount for the canopy to fill up. The plants are primed for forcing as soon as they are transferred into the garden. Fewer plants require a longer waiting period to fill the canopy.