Is soaking seeds necessary before stratification?
Written by
Paul Reynolds
Reviewed by
Prof. Samuel Fitzgerald, Ph.D.Whether or not to soak seeds before stratification depends entirely on the type of seed. Hard-coated seeds like lupines and sweet peas benefit a lot from soaking, whereas seeds that are delicate, like poppies, could be harmed. I change my method according to the seed biology.
Seeds Requiring Soaking
- Hard-coated legumes: Soak 12-24 hours in room-temperature water
- Thick-shelled natives: Nick seed coat before soaking for better absorption
- Large seeds: Use warm water (85°F/30°C) to penetrate dense coats
Seeds to Avoid Soaking
- Tiny seeds like snapdragons: Absorb water too rapidly causing disintegration
- Fuzzy-coated varieties: Water damages protective hairs essential for germination
- Pre-stratified commercial seeds: Check packaging for specific instructions
Optimal Soaking Technique
- Use distilled water to prevent mineral contamination
- Limit soaking duration to 24 hours maximum
- Rinse seeds thoroughly before transferring to stratification medium
Seed germination inhibitors are present in the hard coating of seeds. The soaking also softens the hard shells, allowing water to penetrate. In my test, soaked lupines germinated 70% faster than their dry counterparts. Always soak seeds in room-temperature water to avoid shocking delicate embryos.
The moisture present in most species' stratification media is adequate. Paper towels or damp sand provide gradual hydration. I save soaking for visibly hard seeds that cannot be pressed with a fingernail. Soaking avoids unnecessary seed handling that can injure small seeds.
Be sure to drain seeds after soaking them for stratification. Excessive water in closed containers can lead to the growth of mold. I like to let the air dry on paper towels for about 30 minutes before bagging. This technique controlled moisture and prevented mold from forming in my previous batch of beans.
Research specific details about your seeds using reputable resources. For example, a guide from a native plant society will have the appropriate amount of soaking time. If you're not sure, you can skip the soaking time and check the results. You can always modify this procedure next year, or use germination rates for next year's seeding decisions.
Read the full article: How to Stratify Seeds: Ultimate Methods Guide
