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.