Early Flowering with Far-Red Light

I
started the experiment at the beginning of June. I chose eight plants, four
each in two four-foot long trays. The plants have been growing using
five-gallon containers with planting mix. The nylon rope wicks in the bottom of
the containers draw the water/nutrient solution up through the wicks to keep
the planting mix moist. The plants are being fed a vegetative mix with a pH
between 6 and 6.2, and the solution is kept at about 800 PPM dissolved solids.
These measurements are taken using dipstick testers that are indispensable for
gardeners.

In the
month since they were transplanted, the plants have grown to fill the space and
jumped by two feet or more. At first, they showed the indications of powdery
mildew infestation. A few of the leaves some 1/4 to 1/2 inch circles of
slightly lighter green than the rest of the leaf. I sprayed the plants with an
organic herbal fungicide. The mold was gone the next day. The greenhouse is
moist and stays in the 70s a good part of the time. Since these are the ideal
conditions for mold growth, I decided to spray the plants once a week with a
dilute solution of the fungicide as a preventative.

June 22
marked the first day of summer and the longest day of the year. After that, the
days begin to grow shorter, and the nights grow longer. In order to flower,
most cannabis varieties require about five nights with at least 10.5 to 11
hours of darkness. At this time of the year in San Francisco, sunrise is at 5:53a.m. and sunset at 8:35p.m., a total of nine hours and 18
minutes of darkness. The plants require about 1.5 additional hours of darkness
in order to flower. One way to achieve that is light deprivation. Opaque
curtains are drawn daily from the start of forcing until the flowers are ripe
to increase the dark time to 12 hours.

I’ve
decided to try to force plants to flower using a different technique. As long
as plants receive more red light (which has waves around 680 nm long) than far
red light (which has a wave length of 730 nm) the plant’s regulator,
phytochrome, stays in its active form, and the plants remain in vegetative.
Phytochrome turns to its inactive form over a two-hour period in darkness. If
the plants receive mostly far red, rather than red light for even a brief
period shortly after darkness begins, the phytochrome quickly turns to its
inactive form, which promotes flowering. If the experiment works, it will show
that a 730 nm light flashed on plants after darkness works as well as a
darkening curtain, with a lot less effort and bother. I hung three far red
lights over four of the eight plants, which go on shortly after sunset for 30
minutes. If the experiment works, the plants will start flowering within two
weeks while the controls will remain in vegetative for weeks longer.

GROWING
TIP

As you
read this, most plants are on the cusp of change from vegetative to flowering.
If you think one or more of your plants may be a winner worth preserving , now
is the time to preserve its genetics.

Take
cuttings of each possible winner, mark each one using a tag, then clone them,
then keep them growing vegetatively by placing them under a minimum of 18 hours
of light daily.

After
harvest drying and curing comes testing. Check out the bud from each of the
plants and decide whether they truly are winners. You’ll be a winner too,
because you’ve preserved the genetics for another crop.