From what I've read, short day onions begin producing bulbs when the day is ~12 hours long and getting longer, and finish when it is ~14 hours long. The 12 hour point is always on the equinox, ~March 22, and the 14 hour point varies with latitude, moving closer to March 22 as you go north. Long day onions on the other hand bulb roughly between 14 and 16 hours. Below 30 degrees latitude (Florida and South Texas), the day is never longer than 14 hours, so long day onions never get the trigger to bulb. In practice you need to be above 35' latitude to have enough days longer than 14 hours to get decent onion bulbs out of long day onions. Intermediate day onions bulb around 13-15 hours. In practice the onions are not so precise, some seed companies will give the day-lengths for bulbing of a different seed, and it may vary by up to an hour or two. When an onion is recommended between two latitudes, it's really an indirect way of stating its day-length needs that is easier to figure out. I'm at 37.7' latitude, so pretty close to the long day/short day border, but I'm also near the Pacific ocean, so winter and spring temperatures are warm enough for short day onions to grow. So I've planted long, short and intermediate day type onions to see how they all do. All of them grow identically until bulbing starts, now the short day onions have bulbs larger than golf-balls and the intermediate day onions are starting to swell. The current day length is 14.2 hours, and the longest day for me will be 14.6 hours on the summer solstice, June 21.

No experience with hemlock seeds (although I do know they are notorious for low germination). But, I haven't had damping off for other seedling because, in addition to the air circulation Dax mentions, I also put a fine layer of ground peat moss around my seedlings and water from below. When I water I wont let the peat get saturated and therefore it remains hydrophobic. This, along with the peat's lower pH seems to keep damping off at bay. tj

I do like the height of my bed. It's three 2x10s high so it's a little more than 2 feet. These past two rainy summers it's been really great. My mom has to bail the water out of her ground level garden with a bucket, but my raised bed drains freely. They can be a nuisance in dry years though. You would have to water pretty much every day if it was hot and didn't rain. This current bed was filled with two composters of unfinished compost, then topped off with bagged topsoil which had no added chemicals but wasn't officially organic. I haven't added fertilizer yet since it had a base of compost. This year I bought organic seeds and I will be collecting my own seeds for future years.

You may have harvested the seeds too early. But if one is sprouting, others probably will, too. You have to give them time. Treat the seedlings as you would other seedlings: not too cold, not too soggy, plenty of light, and some air circulation.