Palm Springs, California
Yes. During the winter you can grow vegetatively indoors. When plants get to a height suitable for flowering, place them outside and they will flower under the long dark period.
Most modern hybridized varieties have a critical dark period that is shorter than 12 hours. They start flowering in August or early September if grown outdoors beginning in the spring or early summer. However, when a plant grown under continuous light is placed outdoors, even in mid-summer southern California, as well as other areas along southern tier of the US, they often start flowering immediately. This is especially true of short season varieties.
In the fall, winter and early spring, placing an indoor plant outdoors is not usually a problem because the sun’s intensity is lower and there is much less ultraviolet light. During the brightest periods of the year, leaves not accustomed to sunlight will sunburn and die. New leaves will grow but the plant will be set back. To prevent this, use a spray anti-transpirant. They coat the leaves and clog the stomata, holding water in and blocking some sunlight.
Make sure to keep the plants shielded from street lamps and don’t let the rays of a patio or flashlight come near the plants. These unintentional sources of light in the dark period will mess with the tightness of the buds and may delay ripening.
If you must look at your plants at night, use only green light to illuminate them. Place a piece of green plastic over a flashlight or use a green fluorescent. Plant photo-response is not sensitive to green light so shining it on them will do no harm.
Readers with grow questions (or answers) should send them to Ed at: Ask Ed, PMB 147, 530 Divisadero St., San Francisco, California 94117, USA. You can also email Ed at [email protected], and send queries via his websites at www.ask-ed.net. All featured questions will be rewarded with a copy of Ed’s new book, Best of Ask Ed: Your Marijuana Questions Answered. Sorry, Ed cannot send personal replies to your questions.