What are the negative and positive aspects of growing under 24 hours continuous light for3-4 months prior to placing plants into flowering. I grow both indoors and out. Terry
When plants are being grown vegetatively for flowering indoors they can be exposed to continuous light. They will get a third more light each day than they would under a regimen of 18 hours of light a day. As a result they will grow faster and more luxuriantly than plants receiving only 18 hours of light a day.
People anthropomorphize plants and/or misinterpret the science behind photosynthesis. People need a rest each day and we know that plants are sensitive to the circadian cycle so some people think, “Why shouldn’t plants need a rest period?” The reason is simple. The mechanics of photosynthesis continue as long as the light is on and the nutrients and water available. When plants are actively photosynthesizing they are creating raw ingredients for tissue building. The longer the light is on and the greater its intensity, the more material is produced and the faster the plant grows.
As soon as the plants are placed under the 12-12 on/off ratio, they start to flower. No matter which light regimen they were exposed to previously, clones from the same plant will produce the same high.
There is a “dark reaction” that takes place during photosynthesis. This is a complex group of reactions, but it doesn’t require light to proceed. Some writers have misinterpreted this to mean that it takes place only in darkness, so they figure the plant requires a dark period. They are wrong.
Outdoors, the situation is a little more complex. When plants are placed outdoors in early June in most parts of central Europe, they receive less than 16 hours of daily light. The closer they are to the equator, the fewer hours they receive. Plants that have been lit continuously often are jolted into flowering by this drastic change in light regimen.
Instead, the daily light regimen should be kept at 18 on and 6 off. This will prevent flowering. When plants are transplanted outdoors the shift to 14-16 hours of light a day from 18 hours will not be as drastic as going from continuous light. Most varieties will adapt to the outdoor environment without immediately starting to flower. Instead they will continue to grow vegetatively until late summer, when they will start growing buds.