Seed Scarification

Discussion in 'Plant Propagation' started by JeanetteB, Mar 6, 2008.

  1. JeanetteB

    JeanetteB Member

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    Edgewood Canada
    I have black cohosh seed which apparently is difficult and can take many years to germinate. I have read that the most effective way is to scarify using Gibberellic acid.

    Where can I buy gibberellic acid? Does sulphuric or Muric acid do the same thing?

  2. natureman

    natureman Active Member

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    NY USA- Zone 6b
    -From here

    Gibberellic acid is a plant hormone that stimulates plant stem elongation, and also stimulates seed germinaton. I've never used hormones to make any of my seeds germinate, although Gib. acid may aid in the germination of this. Knicking the seed coat is possible, and almost nessacry for some species (such as Hawaiian baby woodrose) in order for moisture to get inside and stimulate germination. I don't know much about cohosh, but if it does have a seed membrane that seems impermeable/tough_skinned to water, then knick it (just don't scrape the inside, only the shell). Sulfuric and muriatic acids shouldn't be used imo, but that's me. You can probably get gibberellic acid at a plant nursery or hardware store. Although first, I'd try the quoted information above.
  3. abgardeneer

    abgardeneer Active Member

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    Calgary, AB
    Re: Cimicifuga racemosa
    Dr. Norm Deno's work essentially found the following:
    For seeds that had been in dry storage for 6 months, 3 months at 70 deg F, followed by a period at 40 deg F resulted in 100% germination in the 4th week. His data suggests that dry storage enhances germination, and that GA-3 was not effective (Seed Germination Theory and Practice, 2nd Ed, Dr. N. Deno, 1993).

    Just to add, giberellic acid is not available at hardware stores, nor at most garden centers, as it is very much a specialty item, insofar as the gardening public is concerned, anyway. Gardens North (Canada) and J.L. Hudson (US) sell it. It's a naturally occurring fungal compound. I'd recommend reading Deno's books for more fascinating info on it, and the plants that are speculated to have evolved with a "dependency" (time-related, anyway) on giberellic acids for the abatement of mechanisms that delay germination. Giberellic acids should be used with caution (as should any acid), and it should not be assumed that its use will be effective on all seeds - it's use is actually fatal to many seeds. Anyway, there is quite a lot of information published about its effectiveness on different species.

    "Scarification" means to abrade, physially, the hard outer seed coat. It has nothing in particular to do with the use of GA-3. You can scarify seeds by rubbing them across sandpaper or across a flat file, or by shaking them in sand, or by nicking the seed coat with a knife.

    I wouldn't recommend messing around with sulfuric acid for any purpose. Muriatic acid is a solution of HCl (hydrochloric acid), which is effective in dissolving calcite (CaCO3, calcium carbonate), i. e. limestone. I can't think of any particular reason why it would be used on seeds. Scarification or stratification usually provide the germination triggers that are needed.
    Last edited: Mar 7, 2008

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