When a seedling first emerges, it'll take some time to put on roots. During this time, it looks like it's just sitting there, but it's not. All the growth is just going on under the soil where you can't see it. That could be part of the problem.

What's the soil temp? It'll be different than the air temp, sometimes very different. Those three you listed like it warm, both above ground and below, so that could be making them grow slowly and surely is making them germinate slowly and sporadically. I have a lot of seedlings in my unheated greenhouse where the air temp isn't very warm constantly. The overall temps sound like the ones you have, with occasional dips ten degrees below that for a few days (like this past week).

The ones I started three weeks ago are still just an inch or so tall ~ been that way for more than a week. I started them on my warming table (soil warming cable that kicks in at 75 degrees or so). And some I started in mid-January before I got the warming table set up are just now approaching three inches tall and putting on true leaves at two months old.

I don't know if using the Miracle Grow mix is causing any problems, but it may be ~ I've heard that too much fertilizer during sprouting can stunt them (no idea if that's true) and can cause fungal problems (know that's true).

I thought the miracle grow potting mix might have been the problem; that is why i started the second batch using a neutral, sterile, seed starting mix and am looking at the teeny tiniest seedlings i've ever seen. I've been doing this for a lot of years and i'm comparing what i'm seeing to what i've seen in other years.

When i used the old shop lights with gro light bulbs my main problem was lanky growth. I had to keep the bulbs just a couple of inches away from the tops of shoots. But i never saw an emerging seedling be so tiny or take so long to put on growth unless I was doing something wrong. So I figure something is wrong but don't know what it is.

Hey lou m,I noticed that you didnt say anything about the humidity conditions-did you/do you have any type of clear covering over your seeds/seedlings? I do that when I start any kind of seed,cuttings,or if someone gives me plantlets.IT creates that "Greenhouse effect".I have seeds that sprout in 5 days or less,it will perk up any plant that has suffered a variety of different things.The responce by Knittlin raised several excellent points about soil temp..certain seed need a constant 70 degees and as far as the lighting goes,heck,I just have a old floresent fixture that used to be a Beer sign! BUT,it must be as close to the pots/tray as possible,raising it only when the plant height deems it.All in all,I'd say your soil temp is the main problem added to not enough humidity.I use a variety of re-cycled things to cover pots and trays.One of the best is 2-3 liter plastic drink bottles- you remove the label around it,cut off the bottom right before where it starts to curve inward,then set it over the pot.OR depending on pot size(6-in.),set directly onto soil.For smaller pots,use 20oz. bottles..experiment!..for whole trays,get dry-cleaning bag,anything big enough and prop up with sticks,plastic knives,etc.Also,I dont think using the pre-fertilized mix is a good idea,because the seed has everything it needs inside of it's little self!And here's one more thing-it is better to have short healthy seedlings than tall spindly-looking ones while they're growing under artificial light..you want them to have thick,healthy stems and the rest will follow.I dont know how experienced you may be,but I do hope I have helped in some way..heck,I've had the same or worse problems! Good Luck to you and your little friends(that what I call my plants!) Caren

Thank you both but I am not sure about the solution yet. I can't imagine the soil temp would be much lower than air temp after 3 weeks under lights so I don't think that is the problem.

Humidity is something to look at though. I have plastic covers that go over the trays and when i used T12 (shop lights) I covered them. The first ones I started I kept covered but saw mold developing right away and took them off. It may be because the new lights are hotter than the old ones I used to use. And i have wood heat so the relative humidity is usually under 40% this time of year.

thanks again........Lou