Mature tomato plants in 5 gallon buckets usually need a lot more water.

so maybe water every morning?
thanks for your suggestion.

Cant see pics. You say you used bark?

What kind of bark what size. Is it soil conditoner grade. If so and it is the right size it could be the ph if you did not add lime to the bark. The bark has a ph of 4 or so that is way to low, tomatoes like about 5.5-6.5. You could topdress with some lime and see if that works. It could be anothr problem.

If leavs fold up overwatering, leavs fold down underwatering.

the leaves are folding down so I think it might be under watering, I'm gonna give that a try and see what happens...thank you!

Stick your finger in the soil. You should be able to tell if it's too wet or too dry. Don't rely on a set schedule, because the amount of water the plant will need can vary, depending on such things as the weather, the size of the pot, the type of soil mix, size of the plant, etc.

Is there any other reason that tomato leaves would curl up? Like if it's too hot? I've seen plants curl their leaves for protection against heat. At night in the dark when I come home from work I check my tomato plants and some of the plants have curled up leaves, but the next day they are flat again. Could it also be a nighttime thing? I also might be over watering, as it has been very sunny warm and dry for the last 2 weeks.

Sounds like you have large pieces(pieces over an inch ?) of bark in the bottom and threw potting soil on top ,is that correct ?