Flowering In Less Darkness
In Experiments at the Cutting Edge, Part I, I discussed critical dark periods that induce flowering. When the plant repeatedly receives an uninterrupted dark period of that length, flowering is induced. The plant measures darkness as the absence of red light. To stop a plant from flowering, interrupt the dark period with red light such as the light from an incandescent bulb half way the dark period and the plant will continue to grow vegetatively.
When the red light ends it takes the inactive form (which doesnt promote flowering) about two hours to change over to the active form. This can be speeded up considerably by far red light. You cannot see far red light but you can feel it as heat. Incandescent bulbs emit about 10% of their energy as visible light. The other 90% is emitted as far red light. When the light hits a solid object, the energy is converted to heat.
You can make your own far red energy lamp by covering an incandescent bulb with opaque black paper. The visible light is blocked but the far red rays go through the filter. Far red bulbs are available at pet shops where they are sold as black heat lamps.
When far red light comes in contact with the inactive form of the flowering hormone, the hormone is immediately converted to the active form. The far red light doesnt have to remain in contact with the plants longjust a few moments will do.
Photoperiodism is a localized effect. If you had a plant with two branches and one of the branches was given a flowering light regime while the other was given continuous light, the first branch would flower but the second would continue to grow vegetatively. Because the effect is localized, all parts of the plant must be reached with the far red light. Think of applying far red light as you would think of spraying water on the plant. The entire plant and all its vegetation must be dripping with water when you are done. It is in this manner that you have to spray the plant with invisible light. The spraying should take place each evening after dusk or after the lights have been turned off.
The Effects of Far red Light on Outdoor Gardens
(WARNING: THESE METHODS ARE BEING TESTED NOW. THE RESULTS WILL BE AVAILABLE LATER THIS YEAR.)
In an earlier article Project Haiku, I described how to force plants to flower early by covering them each day using an opaque curtain. They were harvested eight weeks after forcing began.
Far red light can substitute for the curtain tossing. In Northern California, where Project Haiku took place, June 22 is the longest day and shortest night of the year; the garden received 14¾ hours of light and 9¼ of darkness. The short dark period prevents flowering. Chemically, the inactive flowering hormone is taking its time, 2 hours worth, to convert to the active form. The plants are under the influence of the flowering hormone for only 7¼ hours, so the plant remains growing vegetatively.
When the plants are sprayed with far red light, the hormones convert over to the active form. If this is done daily at dusk, it gives the plants another two hours under the influence of the active hormone each day. This is a long enough period for them to be induced to grow buds and start flowering. So if a garden was forced in May it will ripen in July. A June forced garden, such as PH, is harvested in August
The main problem with using far red light is that it sometimes induces stem stretching. There is a solution: spray the plants with blue light. Blue light has been used for decades in a few commercial nurseries to keep plants compact and prevent stretching. Plant photoperiodism is not affected by the blue spectrum. After the plants are sprayed with far red light, a spray of blue light keeps the stems short and stocky.
Far red Light Indoors Gardens
(WARNING: FINAL RESULTS FROM THESE EXPERIMENTS HAVE NOT YET BEEN REPORTED)
The typical indoor flowering room spends 12 hours a day, half its time, in darkness. The positive side of this is that the dark period forces the plants to flower. The negative side is that while the plants are in darkness they dont photosynthesize.
A few growers have figured out their plants critical flowering time and increased the lit period by up to an hour and a half. Instead of spending 50% of their time in darkness, they spend only 44%. More importantly they luxuriate under the lights for another 6% of the time. Thats an increase of more than 12% of the lighted period. A corresponding increase in yield should follow.
Using an far red light spray followed by the blue light cuts down the need for as long a dark period as plants are normally given. Imagine if you could reduce the dark period by 2 hours, more than 16% of the lighted period.
If both techniques were used the lighted period would total up to 15½ hours, three and a half more hours each day for creating sugars and energy for growth. The final result: Bigger buds, and more of them.