Seedlings growing very slow

[Eleven11]

Maybe it's the time of year, I'm not sure but I've been having problems growing seedlings. The latest experiment is Romaine and some carrots. Here are some pics.... these are probably 3 or 4 weeks old. They sit in a southern facing window getting full sun when available and the inside temp of the house is usually around 70F. They get watered when the soil looks like it needs it.

I'm not sure what to think. The last batch of Romaine was not much better than this so it was a pain to transplant to the growbeds but they grew ok. I added a recent pic of the lettuce that was transplanted the first part of January.

My next experiment will be planting seed directly in the grow beds.

[attachment=2:17jcg4ja]Romaine seedling.JPG[/attachment:17jcg4ja]
[attachment=1:17jcg4ja]Romaine seedling 2.JPG[/attachment:17jcg4ja]
[attachment=0:17jcg4ja]2.22.12 Growbed 3.2.JPG[/attachment:17jcg4ja]