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Germination experiments

Few of the beets I winter-sowed in February came up. Freezing and thawing in their little pots on the porch wasn't enough to open the tough, knobby little capsules that beet seeds come in.

Yesterday I took a rolling pin to some — trying to press just hard enough to break the capsules open, without smashing the seeds inside. Then I was glad for my nearsightedness, as I picked through the debris to find the actual seeds. I guess I could also just plant the whole smashed mess.

Breaking open the seed coat, or "scarification," originally meant scratching the seed, but we humans keep inventing new substitutions for what seeds go through in the wild. Acid scarification even mimics digestive juices. On some of the beets, I'm trying warm water scarification, leaving the capsules to soak in the cooling water.

As long as I'm experimenting, I go to work on some seeds of aibika (Abelmoschus manihot) that are probably too old. Even fresh ones are as difficult as beets.

First I tried rubbing the eighth-inch seeds between two sheets of medium-grit sandpaper. This ground off some of the seed coats, shedding a brown powder. On others, I used a nail file. After almost a minute, a pale spot appeared: the embryo plant showing through. At first I filed on the eye, figuring that's where the plant had to emerge, to send its initial root down. Then I read directions from the seed company Thompson & Morgan: break the seed coat far from the eye. This will let water in without injuring the delicate structure under the eye. Also they say chip bigger seeds with a knife, and puncture tiny ones with a needle.

I soaked some aibika, too. And some, I put between layers of damp paper towels in a plastic bag; so I can see what sprouts before I plant. This method's called stratification, referring to the layers (strata); people used to make them of soil, sand, compost, and/or vermiculite (sometimes with cheesecloth above and below the seeds, to make it easy to pick them out when germinated). These days everyone usually just mixes it all together, with no layers; still it's called "stratification." This is a risky experiment: stratification's usually done cold. Aibika hates cold — but warm, the seeds may mildew.

I don't really have a place for this tall flowering okra — but if I get a plant to grow, I'll find one!

Photo by C.H. Clark - Scarifying beet seed capsules. On the top, unsmashed capsules. On the bottom row, seeds are on the right; remains of the capsules on the left.

Text and photo © Copyright 2006 Catherine Holmes Clark

Published in the six Nashoba Publications papers on Friday, 2 June 2006

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For more information
  • Seed Germination Database - on The Backyard Gardener site. Info is from Thompson & Morgan Successful Seed Raising Guide (out of print).
  • Biochemical Stimulation of Plant Growth, by Robert Nelson
  • Dr. Norman C. Deno, professor emeritus of chemistry in the Eberly College of Science at Pennsylvania State U, carried on similar experiments — with simple equipment, but much more extensive. He has independently published his results in Seed Germination, Theory and Practice, available for $20.00 postpaid worldwide directly from him at 139 Lenor Dr., State College, PA 16801 USA.
    • A brief synopsis is online on The Seed Site.
    • MegaGro is a product containing Gibberellic acid, which Deno used for one of his main techniques.
    • Seed the Day, by Matthew Holm from Research/Penn State, Vol. 17, no. 1 (March, 1996) - an article about Deno.
  • For results of my experiments, see The Joy of Seedlings.