Advanced Flowering

BobNarley · 05-31-2008, 10:19 AM

Advanced Flowering
Created by Sam Selgnij
Copyright 1986 Ed Rosenthal and Sam Selgnij
In Chapter 25 (Flowering), marijuana's photoperiod response
was described. Most varieties of cannabis flower in response to
changes in the light cycle. This is a foolproof method for a plant to
determine when to flower when it is adapted to a particular loca-
tion. Every year the ratio of dark to light remains the same at a par-
ticular date. Scientists think that plants measure the number of
hours of darkness by producing a hormone, tentatively named
florigen. This hormone has not actually been discovered. The
theory is that when the level of this hormone reaches a critical level,
the plant goes into its reproductive mode.
Through simple experimentation, we know some interesting
things about this plant response. It is a localized response by the
plant. This was discovered by shading one branch of a plant but
leaving the rest of it without a daily dark period. Only the branch
that was shaded flowered. (This is a viable technique to use to sex
plants).
Researchers think that the hormone is produced by the plant
continuously. However, it is destroyed or metabolized by an en-
zyme or hormone which is produced only in the presence of light.
Under natural conditions, the critical level builds up only with the
onset of long nights in the autumn. When the dark cycle is inter-
rupted by light, even for a few minutes or less, the florigen is
destroyed by the plant and the plant starts the buildup to the critical
level over again.
The response to different light cycles is a graduated one. Plants
that initiate flowering at one light/darkness routine flower more
heavily when the amount of darkness is increased. This response is
more pronounced on plants originating from a higher latitude
where the light cycle changes more.
Chrysanthemums are also long night-flowering plants, and
their growth patterns have been studied extensively for use by the
greenhouse industry. Researchers found that the largest flowers
with the highest total weight were grown when the dark cycle
routine was provided each night. When the plants were shaded 6

nights a week, there was a slight diminution of flower size and total
weight. With each additional unshaded night, flower size and
weight dropped.
Cannabis is one of the most widespread plants. It is naturalized
everywhere from the equator to the arctic. (Private cannabis
gardens have also been documented as being grown by scientists
stationed at outposts in the Antarctic - it's not illegal there since
no country has sovereignty). The plant has developed many varia-
tions on the photoperiod response to adjust to different climactic
and latitudinal conditions.
Female plants from equatorial or sub-equatorial zones such as
Colombia, southern Mexico, central Africa, and south India are
absolute photo-determinate (APD). These plants are acclimated to
latitudes in which there is little variation in the light cycle
throughout the year. As long as the dark period falls below a
minimum trigger period, the plant remains in the vegetative growth
cycle. This can go on for years under continuous light conditions.
When the dark period lengthens to a trigger point, the plant
changes its growth pattern to sexual development. If the dark
period falls below the trigger level when the plants are flowering,
the plants easily revert back to vegetative growth.
APD plants are good candidates to flower and regenerate.
Since they respond to the light cycle in a relatively simple way, ir-
regular or interrupted cycles alter growth significantly. Buds are
smaller, leafier, fluffier, looser, and may run. They look a bit like
low-light flowers.
Flower size can be increased by allowing the plants to ripen ful-
ly, then placing them in a continuous light regimen for a few days.
Flowering is triggered again and the plants produce new clusters of
flowers.
Some cannabis varieties are "relative photoperiod deter-
minate" (RPD). These plants have a trigger that they respond to
under normal growing conditions, but when they receive an unusual
light regimen, they respond to the change in the light conditions in
unusual ways. For example, an early flowering indica normally trig-
gers at 10 hours of darkness, but if it is grown under continuous
light and then the darkness cycle is increased to 8 hours, the plant
triggers. Once these plants are triggered, the light cycle has less af-
fect upon them than upon the absolutes. The developing flowers are
not as sensitive to occasional interruption of the darkness cycle.
RPD varieties include mid-and high-range latitude-adapted
plants including Moroccans and southern Africans, early indicas,
commercial hemp and hybrids developed for early harvest
(September or earlier).
RPD varieties are harder to manipulate using the light cycle.
Plants placed into flowering do not revert to vegetative growth as
easily as APD varieties. The plants are harder to regenerate. Light
stress promotes hermaphroditism in these varieties. They are harder
to clone; they take longer and have a lower success rate.
Most males and some extreme northern varieties including the
ruderalis strains fall into a third category which is not photosen-

sitive at all. Both age and development seem to play a role in deter-
mining when these plants flower. For example, a Hungarian
ruderalis developed flowers under continuous light after 8 weeks.
Most varieties of males indicate under continuous light after 3-9
months. Thais and some equatorial sativa males are exceptions and
will not flower until the dark period is increased. Under 18 hours of
light, males indicate sooner than under continuous light.
Cold may hasten sexual expression but not flower development
of some northern varieties.
Some varieties, especially indicas, respond to unnatural light
cycles by showing of photo-period response disorder. Genetic
females turn hermaphroditic when exposed to long dark periods
during early growth.
Chart 27B
MATURATION PATTERNS UNDER NATURAL LIGHT
LENGTH OF FLOWERING
Inductions 3-4 Weeks 5-7 Weeks 8-15 Weeks
Flowering Short Medium Long
Early July 1 2 3

Mid-August-
________ _________ 6
________ 5 _________
4 _________ _________
September

Late October-
__________ _________ 9
_________ 8 _________
7 _________ _________
November
Colombia & Equatorial African 8-9
South African 2
Southern Mexican 5-6
Early Indica 1-2
Late Indica 5
Southern Indian Sativa 8
Thai 9
Ruderalis 1
Nepalese 6
Chilean 1-2
Korean 1-2

05-31-2008, 10:19 AM	#1 (permalink)
BobNarley My Mood: Join Date: May 2007 Location: Mojove Desert-Southern California Posts: 530 gRamz: 13,076 Danks: 26 Danked 17 Times in 14 Posts	Advanced Flowering Advanced Flowering Created by Sam Selgnij Copyright 1986 Ed Rosenthal and Sam Selgnij In Chapter 25 (Flowering), marijuana's photoperiod response was described. Most varieties of cannabis flower in response to changes in the light cycle. This is a foolproof method for a plant to determine when to flower when it is adapted to a particular loca- tion. Every year the ratio of dark to light remains the same at a par- ticular date. Scientists think that plants measure the number of hours of darkness by producing a hormone, tentatively named florigen. This hormone has not actually been discovered. The theory is that when the level of this hormone reaches a critical level, the plant goes into its reproductive mode. Through simple experimentation, we know some interesting things about this plant response. It is a localized response by the plant. This was discovered by shading one branch of a plant but leaving the rest of it without a daily dark period. Only the branch that was shaded flowered. (This is a viable technique to use to sex plants). Researchers think that the hormone is produced by the plant continuously. However, it is destroyed or metabolized by an en- zyme or hormone which is produced only in the presence of light. Under natural conditions, the critical level builds up only with the onset of long nights in the autumn. When the dark cycle is inter- rupted by light, even for a few minutes or less, the florigen is destroyed by the plant and the plant starts the buildup to the critical level over again. The response to different light cycles is a graduated one. Plants that initiate flowering at one light/darkness routine flower more heavily when the amount of darkness is increased. This response is more pronounced on plants originating from a higher latitude where the light cycle changes more. Chrysanthemums are also long night-flowering plants, and their growth patterns have been studied extensively for use by the greenhouse industry. Researchers found that the largest flowers with the highest total weight were grown when the dark cycle routine was provided each night. When the plants were shaded 6 nights a week, there was a slight diminution of flower size and total weight. With each additional unshaded night, flower size and weight dropped. Cannabis is one of the most widespread plants. It is naturalized everywhere from the equator to the arctic. (Private cannabis gardens have also been documented as being grown by scientists stationed at outposts in the Antarctic - it's not illegal there since no country has sovereignty). The plant has developed many varia- tions on the photoperiod response to adjust to different climactic and latitudinal conditions. Female plants from equatorial or sub-equatorial zones such as Colombia, southern Mexico, central Africa, and south India are absolute photo-determinate (APD). These plants are acclimated to latitudes in which there is little variation in the light cycle throughout the year. As long as the dark period falls below a minimum trigger period, the plant remains in the vegetative growth cycle. This can go on for years under continuous light conditions. When the dark period lengthens to a trigger point, the plant changes its growth pattern to sexual development. If the dark period falls below the trigger level when the plants are flowering, the plants easily revert back to vegetative growth. APD plants are good candidates to flower and regenerate. Since they respond to the light cycle in a relatively simple way, ir- regular or interrupted cycles alter growth significantly. Buds are smaller, leafier, fluffier, looser, and may run. They look a bit like low-light flowers. Flower size can be increased by allowing the plants to ripen ful- ly, then placing them in a continuous light regimen for a few days. Flowering is triggered again and the plants produce new clusters of flowers. Some cannabis varieties are "relative photoperiod deter- minate" (RPD). These plants have a trigger that they respond to under normal growing conditions, but when they receive an unusual light regimen, they respond to the change in the light conditions in unusual ways. For example, an early flowering indica normally trig- gers at 10 hours of darkness, but if it is grown under continuous light and then the darkness cycle is increased to 8 hours, the plant triggers. Once these plants are triggered, the light cycle has less af- fect upon them than upon the absolutes. The developing flowers are not as sensitive to occasional interruption of the darkness cycle. RPD varieties include mid-and high-range latitude-adapted plants including Moroccans and southern Africans, early indicas, commercial hemp and hybrids developed for early harvest (September or earlier). RPD varieties are harder to manipulate using the light cycle. Plants placed into flowering do not revert to vegetative growth as easily as APD varieties. The plants are harder to regenerate. Light stress promotes hermaphroditism in these varieties. They are harder to clone; they take longer and have a lower success rate. Most males and some extreme northern varieties including the ruderalis strains fall into a third category which is not photosen- sitive at all. Both age and development seem to play a role in deter- mining when these plants flower. For example, a Hungarian ruderalis developed flowers under continuous light after 8 weeks. Most varieties of males indicate under continuous light after 3-9 months. Thais and some equatorial sativa males are exceptions and will not flower until the dark period is increased. Under 18 hours of light, males indicate sooner than under continuous light. Cold may hasten sexual expression but not flower development of some northern varieties. Some varieties, especially indicas, respond to unnatural light cycles by showing of photo-period response disorder. Genetic females turn hermaphroditic when exposed to long dark periods during early growth. Chart 27B MATURATION PATTERNS UNDER NATURAL LIGHT LENGTH OF FLOWERING Inductions 3-4 Weeks 5-7 Weeks 8-15 Weeks Flowering Short Medium Long Early July 1 2 3 Mid-August- ________ _________ 6 ________ 5 _________ 4 _________ _________ September Late October- __________ _________ 9 _________ 8 _________ 7 _________ _________ November Colombia & Equatorial African 8-9 South African 2 Southern Mexican 5-6 Early Indica 1-2 Late Indica 5 Southern Indian Sativa 8 Thai 9 Ruderalis 1 Nepalese 6 Chilean 1-2 Korean 1-2

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