I'm not sure about the heat mat. However I can tell you my experience in the past with starting hosta seeds. I tried putting them in soil like you have above, and had about the same success you did. Then someone suggested I put them in damp paper towels, put those towels w/ seeds in a ziploc bag, and then put those on top of the refrigerator or someplace warm. I had much more success that way. I was able to see what seeds were germinating, and then placed them into flats from there.
Jen

patience is a virtue ....

heat mat was unnecessary ... unless working in a cold basement ....

just give them another 2 weeks before you start worrying ...

once sprouted... remove from heat .... hosta are a cool season plant... and don't need the heat ..... unless you are working in a very cold area ....

you can increase heat... with the heat generated from your lights.. simply by tenting your light stand in some cheap plastic .... but air flow is just as important as heat ....

what was the quality of your seeds .... they may fail .. regardless of what you do otherwise ....

ken

Legginess is caused by not enough light. Seedlings will virtually 'stretch' for light. Heat mats aid in germination, but seeds will continue germinating even without them. I try to keep my seedling area about 75 degrees.

lights should be kept 2 to 3 inches above the plants ....

to avoid legginess ...

as noted... heat has nothing to do with it ....

ken

Thanks for the input. I think I'll leave the heat in place for at least another week. The flats are in my basement workroom which is only in the low 60's. Some of the seeds came from streaked breeding plants from a well-regarded eBay seller. Others are open-pollinated seeds from my own plants. I will report on my progress later this winter. I just wanted something garden related to keep busy with and have very limited expectations.

Mark

Treemon, there is a seed growers forum, if you are interested google- hosta seed growers forum. Lots of good info on there too. Good luck w/ your seedlings ! ~ Dot

Fungus indoors is always a danger reduced by air movement, use some form of a fan, a really small one will work such as a refrigerator fan.

Hello Mark,

For the last two years I've been experimenting with sowing hostas, in order to find out what the best technique is that works best for me.

The trays are always placed in a room with no heating, so the room temperature can get close to the freezing point.

In the first experiments I always used a small heated indoor greenhouse or an unheated one + heating mat, both covered with a transparent dome.
I tried sowing trays with small individual cells, larger sowing containers, different kinds of sowing medium, additions like mycorrhizal fungi.
In my last experiments, I used the same greenhouses with no extra heating, but a thick "wall" of insulation (rockwool) as a protective casing around the sowing installation. The results from these last experiments were far better than those with extra heating underneath: germination rates are better, growth rate is much faster.

I now use this a my "base rules":
- larger, deep (2")containers are better than tiny undeep ones. In smaller individual cells the soil humidity and temperatures varies considerably and very fast, and the seedlings don't like it.
- I cover the seeds with a thin (?)layer of sowing mixture. This way the seeds are better protected from the heat of the light bulbs. I've even tried a thicker cover, and this word just fine.
- do not use heating mats, try to maintain a higher temperature by using insulation. This will also give you some variation in temperature, which is good, because I learned that different seeds may have a different germinating temperature.
- work as sterile as possible; clean the seeds the best you can. This way you will have less problems with moulds and pathogen fungi, and the cover can be left on longer, which will stimulate growth and gives the slow ones better chances to germinate.

Hope this information is of some use to you (and others),

Greetings from the Hosta Mill,

Rob