Gardening Sowing Seeds

Seeds: Which Side Goes Up?

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Nasturtium seeds (Tropaeolum majus) are lumpy, wrinkled and vaguely round: how should you orient them when you sow them?

You’ve got a seed pack in one hand and you’ve poured a few seeds into the other. The seeds can be of almost any shape: round, oval, long and thin, shaped like a scimitar, etc. All you have to do now is to sow them, but which side should face up?

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Squash (Cucurbita maxima) seeds: the first root will grow from the pointed end. Photo: RoRo, Wikimedia Commons

There is, on every seed, a spot from which the first seed root, the radicle, will appear and it would appear logical to plant it so it faces downward. And sometimes, it’s quite visible. A lot of oval seeds (squash, cucumbers, corn, etc.) have a point and that’s the “down side.” Beans have a depression of a different color from which the radicle will emerge: logically it should point down. Some long seeds, like marigolds, have a tuft at the upper tip, so the opposite end should point down.

Then come round seeds and all those odd-shaped seeds, plus the very fine dustlike ones you can barely see. With these seeds, there is often no particular indication, or a least, no obvious one. What to do about them?

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The seed root will always grow downward, the sprout, upwards.

In fact, though, seed orientation really makes little to no difference. In nature, most seeds end up facing any old way and they still germinate. Geotropism (geo = ground, tropism = growth) takes care of assuring they sprout correctly: the radicle (seed root) will always grow downward, showing “positive geotropism,” while the shoot (plumule) will grow upwards (negative tropism). Auxins (plant hormones) present in the seeds “tell” the root to follow gravitation pull and grow downward and sprouts to defy it and grow upwards.

Interestingly, light is not a factor. Seeds that sprout in the dark will still orient themselves correctly. However, if you sprout seeds in space, where there is nearly no gravity, the radicle and sprout will grow any which way, sometimes both even heading in the same direction!

Is Seed Orientation Important?

You’ll seed Web sites that claim seeds will sprout best if planted with the radical side downwards, as it saves the young seedling time and energy (the root of a seed planted “upside down” would have to travel half way around the seed to head downwards, and vice-versa for the seed sprout). In fact, though, and you can easily test this by sowing the same seed in different positions, it actually seems to make no difference at all. If there is any difference, it is so slight as to be insignificant.

So when you sow seeds, just place them any old way: they’ll do fine!20170509A

Larry Hodgson is one of Canada’s best-known garden communicators. He has notably been editor-in-chief of HousePlant Magazine, Fleurs, Plantes et Jardins, À Fleur de Pot and Houseplant Forum magazines and is currently the garden correspondent for Le Soleil and radio garden commentator for CKIA-FM Radio. He has written for many garden publications in both the United States and Canada, including Canadian Gardening, Harrowsmith, Horticulture, Fine Gardening and Organic Gardening. He also speaks frequently to horticultural groups throughout Canada and the U.S. His book credits include The Garden Lover’s Guide to Canada, Complete Guide to Houseplants, Making the Most of Shade, Perennials for Every Purpose, Annuals for Every Purpose, and Houseplants for Dummies, as well as nearly 60 other titles in English and French. He is a past president of the Garden Writers Association (now Garden Communicators International) and the winner of the prestigious 2006 Garden Media Promoter Award offered by the Perennial Plant Association. He resides in Quebec City, Quebec, Canada.

8 comments on “Seeds: Which Side Goes Up?

  1. How deep do you place the seedlings and what type of soil do you use ?

  2. I have sprout plum seed which way do I put them in soil I have one long root

  3. I am attempting to plant and grow different types of bonsai trees. I have one called the Bodhi Tree, which came in a kit I bought, and has only one very large seed that looks like an acorn, dark acorn look on one end and then the other end is a light brown. Do you have any idea which way it should be planted? Or should I just lay it flat, dark and light ends sideways vs having the dark side of the seed going down and the lighter color going up or vice versa?

    • The angle of seeds really makes no difference to germination (except in some very rare cases). Still, your sideways idea would make sense.

      I’m not sur what you’re going to get. The Bodhi Tree is theoretically Ficus religiosa, but it has tiny seeds. Unless they sent you a dried fruit with the seeds inside.

  4. Carol Swejda

    Hi there, I am trying to grow peanuts this year, and I have started them indoors. they are growing but it looks like they are upside down. I can email you pics as to me they look very strange… 🙂

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