Why Your Cannabis Seeds Aren't Germinating (7 Real Causes)
A seed that sits for a week without cracking is sending you information. Work through these causes in order — the fix is usually cheap and the rest of your pack can still be saved.
1. The temperature is too low
Below 65°F germination slows to a crawl and below 60°F it can stop entirely. A seedling heat mat with a thermostat set to 76°F fixes this for under $30 and is the single highest-return purchase for germination.
2. The towels dried out
A taproot that emerges and then dries is dead. Moisture must be constant, not periodic. Between two plates or in a partly-open zip bag keeps humidity stable enough that you only have to check once a day.
3. You over-soaked
Seeds breathe. A 36-hour soak drowns them. Fifteen hours is plenty; get them into the towel the same day.
4. Old or badly stored seeds
Seeds kept warm, humid, or in daylight lose viability fast. Cool, dark, dry, airtight storage keeps most genetics viable for years. Seeds older than three years germinate slower and at lower rates.
5. Too much handling
Rolling seeds between your fingers, scuffing them aggressively, or poking at an emerging root all cause damage. Move them with clean tweezers by the shell.
6. Chlorinated water
Heavily chlorinated municipal water is not usually fatal, but letting tap water sit uncovered for 24 hours or using filtered water removes one variable.
7. It just needs more time
Some seeds pop in 24 hours, some take 7 days. Before you write off a pack, give it a full week at 76°F with steady moisture.
Frequently asked questions
- Can I still save a seed that hasn't cracked after 5 days?
- Often yes. Move it to a warmer spot around 76-80°F, keep moisture constant, and give it another few days before discarding.
- Should I scuff or file the seed shell?
- Only as a last resort on very old seeds, and very lightly. Damage to the shell often does more harm than good.
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