Pre-soaking Seeds?

I was just wondering what people thought about pre-soaking seeds in general. I know some seeds are always meant to be soaked. I got thinking about it sowing a couple of 'exotic' plants I'm attempting to grow. Soaking seeds was recommended for both to promote rapid germination.

Is it true also that fresh seeds will always sink, older ones will float?

Just wondering if we should soak things like bought wildflower seeds more often.

I've found even quite tiny seeds can be soaked and 'captured' on kitchen roll, so should we just do it a lot more often, or are there seeds that shouldn't be soaked?


  • nutcutletnutcutlet PeterboroughPosts: 26,025

    I scarify and soak the hard legumes but no other hardy perennials. I have a pretty good success rate but I don't do exotics.

  • Never considered soaking wildflower seeds to improver germination, I usually do them in the propagator then shift them into small pots and out into the cold frame. Would be interesting to see if it makes a difference with seed sown in situ.

  • punkdocpunkdoc Sheffield, Derbyshire border.Posts: 6,993

    I soak some large, tough seed, Ricin and Cannas, but nothing else I can think of.

    You wouldn't know a diamond if you held it in your hand
    The things you think are precious, i don't understand
  • Blue OnionBlue Onion Posts: 1,783

    I plan to 'chit' my parsnip seeds on a bit of damp kitchen towel prior to planting.  I also have a variety of old seeds that I'll do the same with, as germination rate is likely to be fairly poor.  Once I see the first sign of growth I'll plant them up into small pots to grow on.  

    It's an extra step of work that I'm unlikely to take with normal seeds.  Could you do a little comparison study?  One row of soaked, one unsoaked.  Maybe you're on to something. image

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  • GemmaJFGemmaJF Posts: 1,197

    I could do that with wildlflower seeds this year Blue Onion, will be planting out plenty in trays soon. Will take some notes and report back.

    I'm particularly interested in whether or not floating and sinking indicates if they are fresh or not. Both the exotics I've done were 'sinkers' out of the packet, which is supposed to be a good sign from the reading round I've been doing. Though I appreciate some seeds may just tend to float because they have more of a husk or different structures to others.

    I'll try the floating and sinking test on known fresh seed from any flowers this year too to see if there is anything to it. image

  • I have done this successfully in the past with Morning Glory.  This year, however, only one of the soaked and initially-germinated seeds has actually germinated properly.  No idea why - but where I had thought it almost fail-safe for some seeds (Morning Glory in particular), I am now re-appraising the method for the future!

  • GemmaJFGemmaJF Posts: 1,197

    Out of interest do you remember if you used tap water or rain water Shrinking Violet? 

  • Fishy65Fishy65 Posts: 2,178

    I pre-soaked lupin seeds Gemma, in a saucer of tap water. Some floated others sank and I have roughly 50% germination I would say. I didn't make a note of which were which though image

  • WelshonionWelshonion Posts: 3,114
    I always germinate sweetcorn on damp kitchen paper and transfer the seed to a pot of soil as soon as the root emerges. From certain seed companies I have 100 percent success.

    Other companies are a dismal failure. I avoid them for all seeds now.
  • Sorry for the delay in answering your question Gemma - I tried to reply on my tablet, but it wouldn't do it for some reason!

    Anyway - it was rainwater that I used as I have in the past.  I put a saucer of water in a heated propagator, then added the seed into the warm water, left overnight, and planted the germinated seed.  But this year it didn't work

    I think that in future I shall try the damp kitchen paper method as indicated by Welshonion - though I would be interested to know which companies were dismal failures, so I could avoid them, too.  (For the record, I have found T & M unreliable with both seeds and bulbs).

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