Why Won't My Seed Germinate? Germination Troubleshooting

3 min read

A cracked cannabis seed that failed to germinate next to a healthy sprouted one

The hardest part of germination is that nothing seems to be happening, so people interfere — more water, more poking, more worry — and interference is what actually kills the seed. Before you write off a dud, run through the real reasons a seed sits there doing nothing. Most of them are fixable, and most of them are us, not the seed.

The short version:

  • Over-soaking (more than ~24 hours in water) drowns and rots the seed — the number one cause
  • Too cold (below ~21°C) stalls germination for days
  • Dried-out paper towel kills the emerging taproot
  • Some seeds are just slow — wait a full 7 days before giving up
  • Genuine duds happen, but they’re rarer than impatience

Want the full breakdown? Keep scrolling.

Did I drown it?

This is the most common killer. A seed needs moisture and oxygen — leave it submerged in water past about 24 hours and it suffocates and rots before it can crack. If your method is “soak until it sprouts,” stop there: soak 12–18 hours, then move to a damp paper towel. The same goes the other way in soil — a seed sitting in saturated, airless mud won’t germinate either. Moist, not soaked, is the whole rule. If you pull a seed out soft, grey and mushy, that’s a drowned one, and no amount of waiting brings it back.

Is it warm enough — and did the towel dry out?

Germination wants about 25°C. Below roughly 21°C it slows right down, and a cold windowsill in an Irish spring can stall a seed for days while you assume it’s dead. Move it somewhere reliably warm — top of the fridge, near a radiator, or on a heat mat (DIG stock them) — which removes the temperature as a variable. The opposite failure is the towel drying out: a taproot that’s just emerged is fragile, and if the paper goes crisp around it, it dies. Check every 12 hours, keep the towel damp, tip off any standing water, and resist opening it every hour — each peek lets warmth and humidity escape.

Am I just not waiting long enough?

Often, yes. The headline figure is 24–72 hours, but that’s typical, not a deadline. Older seeds, harder-shelled varieties, and slightly cool conditions can push it to five, six, even seven days. Give it a full week of warm, moist, undisturbed conditions before you call it. Only declare a seed dead if it’s gone soft and mushy, or if it’s completely unchanged after seven days. If a batch consistently fails despite correct method, then it’s fair to suspect old or poorly stored seeds — but check your method first, because nine times out of ten the fix is “warmer, wetter-but-airier, and leave it alone.”

FAQ

How long before I give up on a seed? Seven days of warm, moist, undisturbed conditions. Most crack in 1–3 days, but slow and older seeds genuinely take up to a week.

Can I save a seed I left soaking too long? If it’s gone soft and grey, no — it’s rotted. Move surviving firm seeds to a damp paper towel straight away and don’t soak the next batch beyond 18 hours.

My seed cracked but the taproot stopped growing — why? Usually it dried out or got too cold. Keep the towel consistently damp and the temperature near 25°C, and handle the taproot as little as possible.

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