Français Do cannabis seeds need to be soaked?
No. Soaking is a way to soften the seed coat and wake the seed up, and it can speed things up for older or very hard seeds. Fresh seeds from a reputable seed bank usually sprout fine without it. Whatever method you choose, the seed needs the same three things: moisture, warmth and air.
How long should you soak a cannabis seed?
- Time: 12 to 24 hours is the usual range. Do not go past 24 hours: a seed left under water for days can drown and rot.
- Water: clean, room-temperature water, about 20 to 25 °C (68 to 77 °F). Cold water slows the seed down and hot water can damage it.
- Regular or feminized: the soak time is the same. The seed type does not change it.
- When to stop: as soon as the seed sinks, or the shell cracks and a white tip appears, take it out and plant it.
Three ways to germinate cannabis seeds
1. Soak, then plant
Drop the seed in a glass of clean water, leave it in a dark spot for 12 to 24 hours, then plant it in a pre-moistened medium once it has cracked or sunk.
2. Paper towel
Place the seeds between two damp (not dripping) paper towels or on a damp towel inside a plate or a zip bag, and keep them warm and dark. Check every day. Move each seed to its pot as soon as the white taproot is about 1 to 2 cm (under an inch) long, and handle it by the seed shell, never the root.
3. Straight into the medium
Plant the seed about 0.5 to 1 cm (roughly half an inch) deep in a lightly moist medium, root end down if you can tell, and cover it loosely. This is the lowest-handling option and the most forgiving for beginners.
Temperature and humidity
Keep the seeds at about 22 to 25 °C (72 to 77 °F) in the dark, with the medium moist but never soggy. Most seeds sprout within 24 to 72 hours, and some take up to a week. Older seeds can be slower.
What not to do
- Do not soak for more than 24 hours.
- Do not use bleach, hydrogen peroxide or compost tea on seeds. We used to suggest a weak bleach pre-soak; we no longer recommend it, because it is unnecessary and can damage the seed.
- Do not overwater the medium. Soggy medium is the most common cause of a seed that never comes up.
- Do not touch the white root with your fingers or tweezers.
Your cannabis seedling's first few weeks
Once the seedling breaks the surface, give it bright light right away so it does not stretch, and keep the medium lightly moist. Water around the stem, not on the leaves, and let the top layer dry slightly between waterings. Wait for the first set of true serrated leaves before you start feeding, and then start light. If you are just getting started, see our beginner seed guide; autoflowers are covered in our autoflower guide.
What size pot should I use?
You can sprout the seed directly in its final pot or in a small starter pot and transplant after two to three weeks. As a general guide, indoor photoperiod plants do well in about 11 to 19 litres (3 to 5 US gallons) and autoflowers in about 7 to 11 litres (2 to 3 US gallons). Outdoor plants usually go in larger containers or in the ground. Autoflowers dislike being transplanted, so many growers plant them directly in the final pot.
Frequently asked questions
How long should I soak cannabis seeds?
Soak them for 12 to 24 hours in clean, room-temperature water, and no longer. Plant them as soon as the shell cracks or the seed sinks.
Do I have to soak seeds before planting?
No. Soaking is optional. The paper towel method and planting straight into a moist medium work just as well for most fresh seeds.
Can I use bleach or hydrogen peroxide to germinate seeds?
We do not recommend it. These treatments are unnecessary for seeds from a reliable source and can harm the seed. Clean water is enough.
What temperature is best for germination?
About 22 to 25 °C (72 to 77 °F), in the dark, with a moist but not soggy medium.
How long does germination take?
Most seeds sprout in 24 to 72 hours. Some need up to a week, and old seeds can take longer.
Should regular and feminized seeds be soaked for different times?
No. Regular and feminized seeds follow the same germination steps and the same soaking limits.
General information, not medical or legal advice. Check the cannabis rules that apply where you live before growing.
