Cannabis Growth Stages: Seed to Harvest Timeline

Germination and Seedling Stage (Weeks 1-3)

The cannabis lifecycle begins with germination, when the seed absorbs water and cracks open to reveal a white taproot. This process takes 24 to 72 hours under optimal conditions: consistent moisture, warmth around 25 degrees Celsius, and darkness. Once the taproot is planted, the seed pushes up through the soil and sheds its shell, revealing two round cotyledon leaves that provide the seedling with stored energy for its first days of life. Within a few days, the first set of true leaves appears — these are the serrated, single-fingered leaves that look distinctly like cannabis. The seedling stage lasts about two to three weeks and is the most delicate period in the plant's life. During this time, the root system is small and easily overwhelmed by too much water. Mist the soil surface with a spray bottle rather than pouring water. Keep the light about 24 inches above the seedling (for LED) and run it 18 hours on, 6 hours off. Humidity should be high, between 65 and 70 percent, which you can achieve by placing a clear dome over the seedling. Temperature should stay between 20 and 25 degrees Celsius. Do not feed any nutrients yet — the seed and the soil provide everything the plant needs at this stage. The seedling is ready to enter veg when it has developed three to four sets of true leaves and the leaves have begun showing the multi-fingered pattern characteristic of cannabis.

Vegetative Stage (Weeks 3-8+)

The vegetative stage is when your cannabis plant builds its structure — the stems, branches, and fan leaves that will eventually support heavy buds. Under 18/6 light, the plant can grow several inches per day during peak veg, and this is when you establish the architecture of your plant through training techniques. Cannabis in veg is hungry for nitrogen, the primary macronutrient that drives leaf and stem growth. Begin feeding at quarter strength after the seedling stage and increase gradually as the plant responds. Watch the color of the leaves: deep green indicates adequate nitrogen, while pale or yellowing lower leaves suggest deficiency. Over-dark, clawing leaves mean too much nitrogen. Watering frequency increases significantly during veg as the root system expands. In a 5-gallon fabric pot, you may water every two to three days. Always water until you see 10-20 percent runoff from the bottom of the pot, which prevents salt buildup in the root zone. This is the ideal time to apply low-stress training by gently bending the main stem and tying it down to expose lower branches to light. Topping — cutting the main growth tip — is best done once the plant has five to six nodes and encourages the plant to develop multiple main colas instead of one. Environmental targets during veg are 22-28 degrees Celsius and 40-60 percent relative humidity. Photoperiod growers decide when to flip to flowering based on space constraints and desired plant size, keeping in mind that most strains will roughly double in height during the flowering stretch.

Flowering Stage (Weeks 8-14 for Photoperiods)

Flowering is triggered in photoperiod strains by switching the light cycle to 12 hours on and 12 hours off. This simulates the shortening days of autumn and signals the plant to begin reproducing. The first one to two weeks after the flip are the pre-flower or stretch phase, during which the plant may grow 50 to 100 percent taller as it jockeys for light. Manage this stretch by keeping the light at an appropriate distance and continuing to tuck or tie down branches. By week two or three of flowering, white pistils emerge in clusters at the nodes and branch tips — these are the beginning of your buds. The plant's nutritional needs shift dramatically during flowering. Reduce nitrogen and increase phosphorus and potassium, switching to a bloom-specific nutrient formula. Many growers also supplement with calcium and magnesium, especially under LED lights. Keep the environment slightly cooler than veg — 20-26 degrees Celsius — and reduce humidity to 40-50 percent to discourage bud rot. By weeks four through six, buds begin to swell and trichomes become visible as a frosty coating on the flowers and nearby leaves. The aroma intensifies considerably during this time. Weeks six through eight (or longer for sativa-dominant strains) are the ripening phase, when buds pack on the most weight and trichomes transition from clear to milky white. Most growers flush the plant with plain water for the final one to two weeks before harvest to remove excess nutrients from the plant tissue, which many believe improves the smoothness of the smoke.

Late Flowering and Harvest Readiness

Knowing exactly when to harvest requires monitoring trichomes — the tiny mushroom-shaped resin glands covering the buds. You need a jeweler's loupe (60x magnification) or a digital microscope to inspect them properly. Clear trichomes indicate the plant is not yet ripe; the THC content has not peaked. Milky or cloudy white trichomes signal peak THC production and maximum potency. Amber trichomes indicate that THC is degrading into CBN, which produces a more sedative, body-heavy effect. Most growers harvest when trichomes are roughly 70-80 percent milky with 10-20 percent amber, striking a balance between cerebral potency and physical relaxation. You can adjust this ratio based on preference — harvest earlier for a more energetic high, later for a heavier stone. Besides trichomes, watch the pistils. When 70-80 percent of the white pistils have darkened and curled inward, the plant is usually in the harvest window. Fan leaves may yellow and drop during the final weeks, which is normal as the plant redirects energy to the flowers. Some strains display beautiful fall colors — purples, reds, and oranges — especially when nighttime temperatures drop below 15 degrees Celsius. Prepare for harvest by cleaning your drying space, gathering trimming scissors, and having hanging lines or drying racks ready. Cut branches in the morning before lights come on, as terpene content is highest when the plant has been in darkness. The transition from living plant to dried and cured bud is just as important as the grow itself, so do not rush this final stage.

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