Cannabis Germination: Seed Starting Step-by-Step

Before you germinate

Start with viable seeds from a reputable source. Old, crushed, or pale green seeds germinate poorly. Dark tiger-striped or solid brown seeds with a hard shell are what you want.

You only need darkness, moisture, and warmth — not nutrients, not strong light, not hydrogen peroxide baths unless you're troubleshooting stubborn seeds.

• Room temp 70–80°F (21–27°C) — a warm closet beats a cold garage
• Distilled or dechlorinated tap water
• Clean hands and tools — seedlings are fragile
• Label strains if running multiple genetics

Paper towel method

The most popular approach: wet two paper towels, wring until damp not dripping, sandwich seeds between them, and place inside a sealed container or between two plates.

Check every 12 hours. When the taproot is ¼–½ inch long, plant tail-down in your medium — don't let roots grow an inch into the towel fibers or they snap on transplant.

Direct sow in soil or coco

Plant seeds ¼–½ inch deep in pre-moistened medium, lightly cover, and keep humidity high with a dome or clear cup until the first true leaves appear.

Less handling means less shock — many experienced growers direct-sow and skip the paper towel entirely. Slightly slower to confirm viability, but simpler.

Seedling environment

First week: gentle light only. A dim LED far from the canopy or a dedicated seedling setting prevents stretching and heat stress. Aim for 200–400 PPFD once cotyledons open.

Humidity 65–75% helps unrooted seedlings — lower gradually after week 2 as roots establish. Overhead misting beats drowning the pot.

• Light: 18/6 schedule from emergence
• Temp: 72–78°F
• RH: 65–75% seedling stage, taper to 55–65% in veg
• No nutrients first 1–2 weeks in soil; 1/4 strength in coco once second set of true leaves shows

Common germination mistakes

Most failed starts are environmental, not bad luck:

• Planting seeds too deep — they exhaust energy before breaking surface
• Overwatering before roots exist — medium should be moist, not mud
• Blasting seedlings with full-strength flower light on day one
• Handling taproots with dry fingers — oils and rough touch damage tissue
• Giving up at 72 hours — some strains take 5–7 days