The Growth Stages of Weed Plants



From a botanical perspective, cannabis plants follow a very involved life cycle that can result in specific care and attention that may be required during these phases. Further, the plants exhibit as male and female varieties which are both required for cultivation and for harvesting crops. Unlike asexual plants which will produce a bud regardless of pollens for activation, hemp plants do require both genders for full maturity and sustainability.

Although there are a number of species and strains of cannabis, cross hybridization has balanced many of the growth requirements between different plants. Since the vegetation does express as male vs. female plants, cross breeding can also be as simple as sterile fertilization of one species with the pollen of another in order to produce a new strain of seed. While grafting has also shown some success for hybridization with cannabis, cross pollination is a more commonly used method since it takes advantage of the natural plant sexuality.

From Seed to Harvest

While cannabis is not native to North America, it has been cultivated throughout nearly all the states at one point or another. Growing conditions in America are similar enough to areas of Britain and Europe from where the plant was initially brought to the colonies, and this tends to allow for natural outdoor cycles that follow the regular spring seedling to fall fruit season for many native herbs. Most plants will take between 3 to 4 months to go from seed to harvest, although different growing conditions can change this range by several weeks.

Although Sativa tends to have a longer growth cycle for maturity as compared with Indica, Sativa also tends to be heartier, more vigorously growing, and have a stronger potency. Indica can still give a considerable yield and some strains of this plant are higher potency, but Sativa is often preferred by growers, even with the longer maturation period.

However, a majority of weed crops in the US are cultivated under highly controlled and protected conditions. This includes green house arrays, even for plants which will later be put to field outdoors. The use of a hot house allows for the ability to force growth in areas with a shorter growing season, but it can also provide a venue for year round crops. This can often make the consideration of the season length a moot point, although it is necessary to understand the general length of time for each of the stages.

Growth Stages:

  • Germination – this is the initial stage when the seedling begins to emerge from the seed. A nutrient rich substrate and warmth and energy from a light source will cause the seed to begin digesting starches within the seed pod and emerge as a basic seedling. This can take as little as 12 hours and as much as three weeks for seedlings to emerge, although this can depend on conditions and species of plant. At this point the seedling will appear as a stalk and two leaves, and no gender can yet be determined for the plant.
  • Seedling – this stage can last anywhere from 1 to 3 weeks, although the timing is less exact than is the plant maturity for this stage. Continued growth will occur as the plant begins to lengthen, but also to produce the first secondary leaves. These appear in pairs, and once the plant has matured to four new leaf pairs, is moving beyond the seedling stage.
  • Vegetative growth – during this stage, the shrub nature of cannabis begins to show more acutely as leaf growth causes the plant to fill out. This exuberant period of growth will also mean that the plants can require 8 to 12 hours of light every day and consistent nutrient rich supplementation to ensure proper maturation. This stage can last for up to two months and is the middle stage for pre-sexual plant maturation.
  • Pre-flowering – this stage can be likened to puberty for the plant. While the expansive leaf growth has slowed down, the plants are now devoting their energy to developing sexual characteristics and producing gonad cells. Although the plants may still not be distinguished as male and female, they are beginning to differentiate. This stage may only last around a week or two.
  • Flowering – at this stage, the plants have reached sexual maturity and males can be distinguished from females. During the flowering stage, female plants can also become fertilized through pollination and this will ensure a next generation. Significant growth traits include the development of buds for both plants, and the flowering of these buds in females. This stage can also last several weeks, with maturation rates still dependent upon both conditions and strains.
  • Seed – during this stage, any male plants that are still present will begin to wither and stop growing. Female plants will continue to mature until the flowers form back into seed pods, and these will darken significantly before they get ready to burst. Retaining fertilized seeds can sustain further cultivation, and pods should be collected after they darken and before they split. This stage can range up to several weeks and can also allow for harvest and seed collection to be accomplished

The Importance of Gender

For cannabis plants, the females are the only ones that contain the active THC compound. This can often cause many growers to discard male plants as soon as they are identified, in order to free up resources for the harvestable plants. However, it should be noted that if male plants are discarded before fertilization takes place, then the female plants will remain sterile and will not produce viable seeds.

This action can greatly inhibit further cultivation, and can also lead to less diversity in strains. With sexual plant reproduction, the first generation offspring has shared traits from both parent plants, in terms of strain characteristics and individual plant variations. While the use of a graft can still revive a strain that no longer has viable seeds, grafting also produces a clone of the mother plant, rather than a combination of genetic material from both parents.

By observing and practicing good plant stewardship, cannabis strains can be further cultivated for beneficial results. Understanding the life cycle of the plant and its social relationships can also provide insight as to what types of nutrients, growth settings, and care practices will also encourage plants to thrive and to produce different ratios of active medicinal principles.