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Sunday, February 5, 2012

Starting Seeds

We've been experimenting around with sowing seeds this winter, so I thought I'd share how that's been going.

Our first attempt was to plant seeds in rock wool, with the idea that we'd transplant the happy little baby plants into hydroton-filled net pots after they sprouted. That worked OK for a few seeds (peas, for instance), but for the most part we were left with itchy fingers and tiny plants that were too small to work with but too large to thrive in the original rock wool cubes we'd allocated.

For my next attempt, I encased each seed in a spit wad of tissue paper before planting it directly in a net pot filled with hydroton. I thought the tissue would keep the seeds moist and keep tiny seeds from falling through the balls of hydroton. I was hoping the tissue would be sufficiently flimsy to get out of the way of the plant when it started to grow.

My daughter, for her part, wanted to use peat pots, which she planted liberally with seeds. She poured lots of very warm water over the plants.

My daughter's seeds sprouted first - making a little carpet of green in her container. That was all well and good until it came time to transplant the little plants. It was nasty hard, and lots of individual plants were damaged in the process.

My seeds eventually sprouted, except for some old spinach seeds that likely were no longer viable. The spit wad idea worked great, and since the plants were already growing in hydroton, there was no need to handle the plants. All I had to do was plop my net pots into my floating raft out in the greenhouse.

Unfortunately, a fair number of the plants we set out in the greenhouse have "failed to thrive." All of the ones that haven't thrived are plants from seeds we initially grew in either rock wool or peat, the ones that had to be transplanted into hydroton. So taking all the good ideas and getting rid of the rest, here's my plan for planting seedlings as I wait for winter to end.

  • Encase the seeds I'm about to plant in a bit of tissue. I used a single ply of facial tissue, torn in 1/2" strips, then cut about 1/2-1" long. I put the seed in the center and fold the tissue over it. Then I moisten the folded square of tissue (licking works for me) and roll it into a ball or wad.

  • I fill a net pot 3/4 full of hydroton and place two of the seed spit wads on top.
  • Next I toss a few more balls of hydroton on top to cover the seeds and fill the netpot.
  • I arrange the filled net pots into a plastic container (to which I have a lid).
  • I fill the plastic container with nicely warm water so it almost reaches the top of the net pots.
  • Last thing for today, put on a lid and stick the plastic container somewhere dark and warm. I've found I can put it on top of some electrical appliance, where the waste heat keeps things warmer than average.

  • Tomorrow I will drain off most of the water and wait. If I'm right, I should see little sprouts as soon as my daughter got sprouts. If so, I can move these plants to the floating raft in my greenhouse as early as next week.


  1. I'm curious how well this has worked, and if you have made any modifications. I too have experimented with many ideas, and agree that planting directly in the net pot is best.

    Jon Parr recently passed a nice trick on to me. He mists the plants and surrounding area lightly with hydrogen peroxide to kill spores while handling, and to help prevent any spores from going airborne. This helps prevent pythium.

  2. My daughter's traditional seed sowing techniques worked well, and since she sowed large numbers of seeds in each pot, her seedlings ended up providing the bulk of the plants for last year.

    I love the idea of misting the plants with hydrogen peroxide!

  3. This past February I ended up just direct-seeding my garden. I broadcast the seeds, and many of them came up just fine. Because the plants were in full sun, they've grown compactly. Given the ease with which one can re-arrange plants in an aquaponic garden, I now find myself with more plants than I can use in my garden. Luckily, between me and my rabbit, I don't think it'll be a problem consuming the excess...

    For those reaching this post from a search engine, let me mention that I ended up getting tapped to write The Complete Idiot's Guide to Aquaponic Gardening for Penguin Book Group. The book is now available for purchase at It includes lots of DIY plans as well as everything I wished I could have found in a book back when I was starting out (which wasn't very long ago...). So far the reviews are good!

  4. Start your seeds in paperntowels, when u have taproots about an ninch long then put then into hydroton, tap root down, the root will prevent the seed from falling, eliminating the need for "spit wads"