I sow the hosta seeds in quart-sized plastic plant pots, hopefully labeled and one variety to a pot. For soil, I use a bagged potting mix for seedlings because it has given me better results than any of the other starting mixes I have tried. I fill each pot nearly full with potting mix and press it down lightly. Then I scatter seeds over the top, add another sprinkling of potting mix to cover the seeds, and place the soil-filled pots in trays of water until the soil surface is thoroughly damp. I let each pot drain for several minutes, seal it in a large plastic bag, and put it a warmish place. I check the pots every few days for signs of germination, and usually within two weeks there will be some seedlings starting to pop up out of the soil. At this point I remove the plastic bag and place the pots with the seedlings under lights for about ten to twelve hours each day.
When the seedlings have developed a few leaves, I transplant each one into a small two ounce cup and then after further growth, into a four ounce cup. I have found that inexpensive plastic cups are great for this, especially the transparent cups that show how the roots are developing. I disinfect and re-use the same cups year after year. Eventually I transplant the seedlings into one quart plastic pots, which are large enough to accommodate the seedling until it is transplanted outside in the spring. Hosta seedlings thrive on frequent transplanting. I use fresh potting soil each time I transplant (in the spring I add the “used” soil to the gardens outside). I bottom water only, so all my transplanting cups and pots have holes in the bottoms.
Not every hosta produces seed pods. Some hostas produce huge numbers of pods and seeds… others produce pods but very few seeds, and sometimes seeds are not viable and will not germinate. I have found that germination is often poor with purchased seeds, but the germination rate for seeds I collect from my own hostas is astonishingly high. Hosta seeds are ready to be harvested when the seeds have turned black, and for me, the best time to start seedlings is sometime in January. By the time I transplant them outside in late May, the seedlings will have a large, well-developed root system. Many will have already produced blossoms.
The differences between the hostas I collect seed from and the hostas I grow from that seed are amazing. For example, I now have several tiny miniatures that came from seed I collected from large hostas. Leaf color, leaf shape, and leaf texture will also vary tremendously from the parent hosta and from seedling to seedling, even though they may start out looking pretty much alike. Although it is true that most of the hostas grown from seed will be a solid color, that doesn’t always happen. Some of my earliest seedlings from solid color parents are now showing blue or gold edges. When seeds from streaked hostas are planted, some of the seedlings should be streaked, but many will be a solid color. Some of these will develop streaks… other seedlings will start out as streaked and mature into a solid color.
I never cull any of my hosta seedlings… partly because culling goes against my philosophy, and partly because a seedling that doesn’t look very promising at a few months or a year old will often turn into a beauty. One of my earlier seedlings in particular looked very ordinary for its first few years. This year its leaves are very twisted and almost black, and are so thick and tough they look and feel like shiny, heavy vinyl. It is really a quite spectacular plant… one I would not have if that rather ugly seedling had been culled. That is what I enjoy so much about growing hostas from seeds… you never really know what the results will be.