5 days ago, I planted 2 varieties of onion seeds. I soaked them for 48 hours, then planted in a 72 cell jiffy tray filled with sterilized organic jiffy seed starter mix. The starter mixture was vaguely moist, enough to produce some condensation, but not a ton. I covered it with the clear plastic lid, with some fabric over that to keep it dark (per online instructions that I found).

Today, we noticed that most of them had germinated, although the seed pods were still on the stems. We removed the lid and noticed some fungus - that white hairy stuff. We took off the lid and put the lights on for a few hours (2 T8's - daylight - about 2-3" over the seedlings.

I checked a few hours later and the seedlings were all limp and laying on the soil surface, although the fungus seemed to be clearing up. The potting material was pretty much dry, so I bottom watered and covered it back up for the night.

Does that sound like the right tactic? I know that it's bad to overwater, but everything was so, so dry...I was actually pretty shocked that they even germinated. Still, we have some fungus issues and I know the water will exacerbate that.

Your choice of potting medium may make it a bit difficult to avoid diseases. Fine textured mixes can cause a lot of problems when trying to balance the moisture content.

Now that the seeds have germinated, you should probably keep the cover off so that the whole thing can be exposed to air. Good light, air circulation, and very careful watering techniques are all important to avoid those dreaded 'damping off' diseases so common to seedlings. Excess humidity and moisture, darkness, lack of air circulation will invite problems. Those fungual spores are ubiquitous.

Many people have reported good success at keeping fungus infections at bay with cinnamon sprinkled on the soil surface or with diluted chamomile tea used to water the flats (or mist the surface). You could even dilute some hydrogen peroxide to mist on the soil surface. Mix household peroxide (3%) at the rate of 1 ounce per quart of water. It can also be used to water the plants.

Be sure that you pull the plug on your heat mats, if you used any. Extra heat isn't required after germination.

I gave them some water last night and today...I think I was underwatering for fear of over watering. It's good to know that the dark isn't needed, sometimes it's hard to sift through all of the info out there.

There's no sign of fungus anymore, but I have some cinnamon at the ready.

As for the potting medium, what is recommended?

Also, should I anticipate problems with the 72 cell trays? I did notice that when I bottom watered some cells were moist while others were bone dry. I switched to a mist to avoid that. What other problems should I expect. Yikes!

Thanks again!