Short answer: soak small brassica seeds (broccoli, kale, bok choy) for 1 to 4 hours, small legumes (alfalfa, clover) for 4 to 12 hours, and beans, peas and grains for 6 to 12 hours. Don't soak gel-forming seeds like chia, basil, cress or arugula. Use cool water and don't leave seeds soaking much past the recommended time.
Why soak seeds for sprouting?
A dry seed is dormant. Soaking lets it take up water fast, which wakes up the enzymes inside and starts growth. After the soak, all the seed needs is to stay damp, not wet. That's why the routine is "soak once, then rinse and drain."
How long to soak seeds for sprouting: the chart
| Seed | Soak time | Notes |
|---|---|---|
| Broccoli | 1–2 hours | Longer can stop it sprouting |
| Bok choy, kohlrabi | 1–2 hours | Small brassicas soak fast |
| Kale | 2–8 hours | |
| Red cabbage | 4–6 hours | |
| Alfalfa | 4–12 hours | Forgiving |
| Clover | 4–8 hours | |
| Radish | 4–8 hours | |
| Quinoa | 4–8 hours | Rinse off saponins first |
| Sunflower | 4–8 hours | |
| Peas | 4–8 hours | Use plenty of water |
| Mung beans | 6–8 hours | |
| Lentils | 6–12 hours | |
| Chickpeas | 6–12 hours | |
| Fenugreek | 6–12 hours | |
| Wheat | 8–12 hours | |
| Chia, basil, cress, arugula | No soak | Gel-forming: mist on a plate |
These times come from Sprouting.com's product pages where available.1 Every seed is listed in the sprouting calendar, and the sprouting calculator gives the soak time and harvest date for any seed.
Why over-soaking is a problem
Seeds need air as well as water. Left under water too long, some seeds run out of oxygen and stop growing. Small brassica seeds are the most sensitive. Sprouting.com warns that soaking broccoli for longer than 2 hours can make it lose germination.1
Long soaks in a warm room can also make seeds sour before they've even started. If your seeds smell bad after soaking, rinse them well. If the smell doesn't go away, start again.
Gel-forming seeds: don't soak
Chia, basil, cress, flax and arugula grow a sticky gel when wet. Soaked, they turn into a clump that can't drain. Instead:
- Mist a plate or tray lined with a damp paper towel.
- Sprinkle the dry seed thinly over it.
- Mist again and keep it loosely covered.
See how to sprout chia.
Soaking tips
- Use enough water. Cover seeds with about three times their volume. Big seeds like peas absorb a lot.
- Cool water is best. Warm water speeds spoilage; hot water can kill seeds.
- Rinse before and after. A rinse before soaking removes dust. A rinse after removes the soak water.
- Overnight is fine for beans. For small brassicas, set a timer.
- Hot kitchen? Soak beans in the fridge, or change the water halfway.
After soaking, follow the step-by-step sprouting guide for draining and rinsing.
Seeds in this article
Frequently asked questions
How long do I soak mung beans, lentils and alfalfa?
Soak mung beans for 6 to 8 hours, lentils for 6 to 12 hours and alfalfa for 4 to 12 hours, in cool water. Don't soak much longer than the time shown. Over-soaked seed can ferment and smell sour.
Can you soak seeds too long?
Yes. Some small seeds, like broccoli, can stop sprouting if they soak too long. Sprouting.com warns that soaking broccoli for more than 2 hours can cut germination. Long soaks in warm water can also make seeds sour.
Do all seeds need soaking before sprouting?
No. Gel-forming seeds like chia, basil, cress, flax and arugula should go in dry and be misted. Most other seeds sprout faster and more evenly after a soak.
Should I use warm or cold water to soak seeds?
Cool to room-temperature water. Warm water speeds soaking but also speeds spoilage. Hot water can kill seeds. In a hot kitchen, soak in the fridge or change the water halfway.
Why do seeds need soaking?
A dry seed is dormant. Soaking lets it take up water quickly, which wakes up the enzymes that start growth. After soaking, you only need to keep the seed damp.
Written by Michael
A passionate sprouting professional sharing practical tips for growing sprouts and microgreens at home. More about Michael
Sources
- Sprouting.com (Mumm's Sprouting Seeds). Product pages: days to sprout, soak time and yield for each seed. Link
