For the weed farmer, the way to grow weed, the foremost vital plant/environment interaction to know is that the influence of the photoperiod. The photoperiod is that the daily variety of hours of day (light) vs. night (dark). In nature, long nights signal the plant that winter is returning which it’s time to flowers and manufacture seeds. As long because the day-length is long, the plants continue vegetative growth. If feminine flowers do seem, there’ll solely be a couple of. These flowers won’t type the characteristic giant clusters or buds. If the times area unit too short, the plants flowers early on, and stay little and underdeveloped.
The plant “senses” the longer nights by an on the spot interaction with lightweight. A flowering endocrine is gift throughout all stages of growth. This endocrine is sensitive to lightweight and is rendered inactive by even low levels of sunshine. once the dark periods area unit long enough, the hormones increase to a vital level that triggers the generative cycle. Vegetative growth ends and flowering begins.
The natural photoperiod changes with the passing of seasons. within the hemisphere, the length of daylight is longest on June 21. Day-length step by step decreases till it reaches its shortest period on December twenty two.
The duration of daylight then begins to extend until the cycle is completed the subsequent June 21.
Because the Earth is tilted on its axis to the sun, day-length also depends on position (or latitude) on Earth. As one moves closer to the equator, changes in the photoperiod are less drastic over the course of a year. At the equator (0 degrees altitude) day length lasts about 12.5 hours on June 21 and 11.5 hours on December 22. In Maine (about 45 degrees north), day-length varies between about 16 and nine hours. Near the Arctic Circle on June 21 there is no night. On December 22 the whole day is dark. The longer day-length toward the north prevents weed from flowering until later in the season. Over most of the northern half of the country, flowering is often so late that development cannot be completed before the onset of cold weather and heavy frosts.
The actual length of day largely depends on local conditions, such as cloud cover, altitude, and terrain. On a flat Midwest plain, the effective length of day is about 30 minutes longer than sunrise to sunset. In practical terms, it is little help to calculate the photoperiod, but it is important to realize how it affects the plants and how you can use it to you advantage.
Cannabis generally needs about two weeks of successive long nights before the first flowers appear. The photoperiod necessary for flowering will vary slight with
(1) the variety, (2) the age of the plant, (3) its sex, and (4) growing conditions.
- Cannabis varieties originating from more northerly climes (short growing seasons) react to as little as nine hours of night. Most of these are hemp and seed varieties that are acclimated to short growing seasons, such as the weedy hemp’s of Minnesota or southern Canada. Varieties from more southerly latitudes need longer nights with 11 to 13 hours of darkness. Since most weed plants are acclimated to southerly latitudes, they need the longer nights to flower.
- To be on the safe side, if you give Cannabis plant dark periods of 13 or more hours, each night for two weeks, this should be enough to trigger flowering.
- The older a plant (the more physiologically developed), the quicker it responds to long nights. Plants five or six months old sometimes form visible flowers after only four long nights. Young weed plants (a month or so of age) can take up to four weeks to respond to long nights of 16 hours.
- Both male and female Cannabis are long-night plants. Both will flower when given about two weeks of long nights. The male plant, however, can typically flower totally underneath terribly long days (18 hours) and short nights (six hours). Males typically flowers at concerning constant time they’d if they were growing in their original surroundings. for many weed plants this happens throughout the third to fifth month.
- Growing conditions have an effect on flowering in many ways (see Chapter 12). Cool temperatures (about 50F) prevent the flowering response. Cool temperatures or typically poor growing conditions have an effect on flowering indirectly. Flower development is slower, and longer is required to achieve full bloom. underneath adverse conditions, feminine buds won’t develop to full size.
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