Cannabis Cultivation: Phases from Germination to Harvest

Since the Cannabis Act (KCanG), the private cultivation of up to three cannabis plants for adults in Germany is legal. What sounds simple has a clear biological process: cannabis goes through several growth phases, each requiring different conditions. A guide through the complete cultivation cycle.

What KCanG allows (and doesn’t allow) for personal cultivation

Before buying the first seeds, the legal framework:

• Allowed: Up to 3 living cannabis plants at the same time, for people aged 18 and older, at the place of residence or usual place of stay
• Storage: Up to 50 g of personal cultivation harvest at home (the 25 g outdoor limit does not apply to cultivation)
• Child protection: Plants must be inaccessible to minors — a lockable room or greenhouse is recommended
• Not allowed: Sale, distribution, more than 3 plants, cultivation in public areas
• Seeds: Seeds may be purchased for personal cultivation — from social clubs or authorized sellers

Phase 1: Germination (3–10 days)

It all starts with the seed:

• Seed preparation: Soak the seeds in lukewarm water (21–24°C) for 12–24 hours — the hydrophobic shell softens, the germination process begins
• Germination method: Place the seeds between damp (not wet) paper towels, keep them warm (22–25°C) and in the dark. After 1–5 days, the radicle appears
• Planting: Once the radicle is 5–10 mm long: plant it with the radicle facing down 1–2 cm deep into a light germination substrate (e.g. coco, peat). Do not touch — the germinating plant is very sensitive
• Light: After germination: 18 hours of light / 6 hours of darkness (indoor). Weak LED or T5 tubes are sufficient
• Substrate: Nutrient-poor germination substrate — too many nutrients can burn the seedling’s root system

Phase 2: Seedling (2–3 weeks)

The first true leaves appear:

• Cotyledons (seed leaves): The first two oval leaves — provide the seedling with energy from the seed
• First real leaves: Cannabis-typical, serrated leaves appear after 3–7 days. First single-fingered, then three-fingered growing
• Light: 18/6 hours. Lamp not too close (heat stress) — LED: approx. 50–60 cm distance
• Watering: Water sparingly. Too much water = most common mistake with seedlings. Let the surface dry slightly
• Humidity: 60–70% ideal. If you place a clear dome over the seedling, you retain moisture

Phase 3: Vegetative phase (4–8 weeks indoor / longer outdoor)

The plant builds mass — the foundation for the harvest:

• Indoor light cycle: 18 hours light / 6 hours dark. Photoperiodic strains remain in vegetative growth as long as the light cycle is correct. Autoflowering strains flower regardless of this
• Nutrients: Nitrogen-heavy (N-P-K: high-low-medium). Cannabis needs a lot of nitrogen during the vegetative phase for leaf and stem growth
• Watering: More than in seedling phase, but always do a “Lift-Test” — lift the pot, if light → water, if heavy → wait
• Training (Topping, LST): Vegetative phase is ideal for training techniques. Topping (cutting off the tip) promotes multiple main colas. LST (Low Stress Training) bends branches horizontally — more light surface
• Outdoor: Plant from May/June — cannabis grows vegetatively until the natural light change in August (under 14–16 hours of daylight flowering begins)

Phase 4: Flowering phase (7–12 weeks indoor)

The most important phase — here buds and trichomes develop:

• Indoor light cycle: Switching to 12 hours light / 12 hours dark triggers flowering in photoperiodic strains. The dark period must be absolutely lightproof
• Early flowering (Weeks 1–3): Bud sites appear, plant stretches (stretching phase — can double in height). White pistils become visible
• Full Bloom (Week 4–8): Buds grow tightly together, trichomes become visible and milky. Aroma becomes more intense. Nutrient demand: phosphorus and potassium focused (reduce N)
• Maturity Phase (Week 8–12): Pistils change color from white to orange/brown. Trichomes: clear → milky → amber. Reliable determination of harvest time only with magnifying glass/microscope
• Flush (Rinsing): In the last 1–2 weeks, water only – removes nutrient residues in the substrate. Improves the taste of the harvested buds

Phase 5: Harvest, Drying and Curing

The quality of the harvest depends largely on post-harvest processing:

• Harvest: Cut branches, remove large leaves (Fan Leaves). Leave “Sugar Leaves” near the buds according to taste or trim them directly
• Drying: Hang branches upside down on strings. Room: 18–21°C, 45–55% humidity, no direct light, slight air circulation. Duration: 10–14 days. Dried too quickly = hay taste
• Curing (Curing): Flowers in airtight glass containers — open daily for 15–20 minutes (burping) for 4–8 weeks. Chlorophyll and residual moisture escape, terpenes and cannabinoids improve. Most important step for flavor and smooth effect
• Control: Hygrometer in jars — 60–65% RH ideal. Over 70% = mold risk

Storing cannabis properly after harvest: Cannabis Storage. KCanG rules in detail: Cannabis Law Germany. Assessing the quality of homegrown cannabis: Recognizing Cannabis Quality.

What happens to cannabis after harvest — making oil or butter yourself: Making Cannabis Oil: Decarboxylation and Infusion — explained: decarboxylation, oil infusion, THC calculation, and safe dosing.

Frequently Asked Questions About Cannabis Cultivation