Problems with Young Plants

I have 12 young plants about 3 weeks old, and on just about all of them the tips of the first and second set of leaves(the first sprouting leaves and the leaves that grow first) are turning brown/yellow and 2 or 3 of them are also very "droopy". I dont think they have been getting enough sunlight as they need but then again not all plant are "droopy". I am also not sure if i am overwatering. I water about every 2 days or when the soil just looks real dry. But all the plants are in a box with no drainage but havent had problems til now. I planed to transplant them outside but it has been real cold and raining alot with little sunlight since i started them. I havent used any fertizlers yet just enriched soil for the first part of growth. Can anyon help me?

The brown / yellowing happend to my young plants to, Its because your continer has no drainage and sediment / water is building up at the bottom. Drill new drainage holes in your container or transplant them to a container with good drainage.

I just put my finger down to the bottom of the soil and it moist but not soaked.