Light might be too bright.

curling up is sometimes due to too high a rate of transpiration. whats your temp?humidity?

are the leaves curling up from the edges towards the center?

the curling is mainly on the lettuce and spinach. I have moved the light farther and that seems to be helping. The leaves are curling like a cork screw, in a spiral fashion.

thanks for the help!

Shop lights? Probably not too much light. But lettuce and spinach prefer lower temperatures and tomatoes like higher. What are your hi and lo temps running?

The lows are about 40 degrees or more, the highs would be 60-65. They are in a attached garage that houses the furnance, so it says slightly cooler than the rest of the house.

I'm not an expert veggie grower, but that sounds OK for the leafy veggies. Could there be some sort of fumes coming from the furnace that the plants don't like?

They could be planted too close together too.