Marijuana Grow Basics by Jorge Cervantes
Cannabis is an annual plant that normally produces seeds to successfully complete its life cycle. Marijuana is a dioecious plant, being either male (pollen-producing) or female (ovule and seed-producing). However, intersesx (aka hermaphrodite) plants with both male and female flowers can also occur.
In nature, cannabis flowers in the fall, after long days of summer. The long nights and short days of autumn signal marijuana to start flowering. Plants are normally either male or female.
Growth patterns and chemistry change during flowering: stems elongate; leaves grow progressively fewer blades; cannabinoid production slows at first, then accelerates; and flower formation is rapid at first, then slows. Nutrient needs change as growth stages change. Plants focus on flower production rather than vegetative growth. green leafy growth, requiring nitrogen, slows. Phosphorous and potassium uptake increase to promote floral formation. Shortly before the flowering stage, growers change to a “super bloom” fertilizer formula with less nitrogen and more potassium and phosphorus. Always flush or leach soil with water two or three days before changing to the flowering fertilizer.
When flowers are full of ripe, mature seeds, the female will die, having successfully completed her life cycle. The male completes his life cycle and dies after producing and dispersing all his pollen into the wind, in search of receptive female pistils.
Induce flowering indoors by giving plants more hours of total darkness and fewer hours of light. Give cannabis 12 hours of uninterrupted darkness and 12 hours of light to induce visible signs of flowering in two weeks or less. This program is effective in all but the latest-blooming pure sativa strains.
Often, when using low-nitrogen, high-phosphorous and potassium bloom formulas, large older leaves yellow or turn purple during flowering. Such fertilizers make buds swell with resinous growth.
Water intake of flowering plants is usually somewhat less than during the vegetative stage. Adequate water during flowering is important for plants to carry on internal chemistry and resin production. Withholding water to “stress” a plant will actually stunt growth and diminish yield.
Inducing flowering in cannabis grown from seed with a 12/12 day/night photoperiod will cause plants to show sex, male or female. Once the sex of the plant is guaranteed, males are almost always harvested before they shed pollen, and females are coaxed into higher yields. Once the photoperiod is set, disrupting it will cause plants to suffer stress. If they suffer enough stress, hermaphrodite tendencies increase.
When given a 12/12 day/night photoperiod, male cannabis reaches maturity and flowers one to two weeks before females. However, plants do not necessarily need a 12/12 day/night photoperiod to grow flowers and shed pollen. Some male plants flower under long days and short nights as well, but these generally produce fewer flowers.
Once male calyxes show, pollen develops quickly and can disperse within a very short time. There is always a flower sack that opens early and sheds pollen, often within 24 hours or less! To avoid pollination problems, remove males as soon as they are distinguished. If growing male plants, always isolate them from females, to prevent accidental pollination.
Female cannabis is prized for heavy, potent resin production and weighty flower yield. ideal female plants grow squat and bushy with branches close together on the stem and dense foliage on branches. In most strains, the first signs of female flowers appear one to three weeks after inducing flowering with the 12-hour photoperiod.
Female flowers initially appear near the top of the terminal ud and gradually develop on lower branches starting at the tips and moving downward. Flowers have two small one-quarter- t one-half-inch (6-12 mm) fuzzy white hairs called “pistils” that form a V. The set of pistils is attached at the base to an ovule, which is contained in a light green pod called a calyx. Pistil-packed calyxes from dense clusters of buds along stems. A cluster of buds is often called a “top” or “cola”. The masses of cayxes develop rapidly for the first four or five weeks, after which they grow at a slower rate. Buds put on much of their harvest weight as they swell during the last two or three weeks of growth. Pure sativas, including Thai varieties, can flower for four months or longer! Onve the ovule has been fertilized by male pollen, rapid calyx formation and resin production slow, and seed growth starts.
Sinsemilla is derived from two Spanish words: “sin” = without and “semilla” = seed. Sinsemilla is the word that describes flowering female cannabis tops that have not been fertilized by male pollen.
Highly prized sinsemilla buds are the most potent part of any strain, with a proportionately large volume of THC per flower bud. When females’ flowering is at their peak, pistils swell and swell. Soon they change in color, most often from white to amber and, eventually, to reddish-brown.
Sinsemilla is all smoke with no seeds! Unpollinated female plants continue to flower until calyx formation and resin production peak out – six to ten weeks after turning the lights to 12 hours. During six to ten weeks of flowering, calyxes develop and swell along the stem, yielding more high-quality buds than pollinated, seeded flowers.
Make any female marijuana sinsemilla by removing male plants as soon as they are identified. Removing males virtually guarantees that male pollen will not fertilize female pistils, but sometimes premature male flowers shed a few early grains of pollen. Sometimes and intersex (hermaphrodite) with a few male flowers will sprout on a predominately female plant. Pollen dispersed from wild or cultivated male cannabis plants could also be floating in the air.
Intersex or Hermaphrodite Flowers
Intersex or hermaphrodite flowers may occur, sometimes near the end of the blooming cycle, though occasionally they appear earlier. Plants that flower past peak potency are most prone to show intersex flowers. Intersex plants are more common in some strains.