Growing tomatoes in pots outside?

We started with tomato plants in pots on the concrete patio. We kept them well-watered. One plant had leaves to start curling just a bit around the bottom. The variety for this plant is "Big Boy."

I became concerned the sun-heated patio and the exposed sides of the pots in lots and lots of Southern sun were resulting in roots and the pot soil's becoming too warm.

I buried the pots in the yard to allow for cooler pot soil and roots. I kept the plants in the pots to conserve and concentrate the watering around each plant rather than have it seep outward from them.

One plant of another variety has about nineteen tomatoes developing. That plant is a bit darker green, and I'm thinking it may have gotten more fertilizer early on. The other plants are a healthy green but not as dark. Some other plants have begun to develop small tomatoes.

But this one plant still has somewhat curled leaves around its bottom of foilage and is not producing. I recall that this one got some top roots exposed a bit, I think due to watering, before I recently put mulch around the bases of the plants.

My theory is that there was some root "baking" early on and that this one plant has not fully recovered from that.

What are your thoughts? And what about the idea of buried pots as a method of growing garden plants for concentrating the fertilizer and water?

Thanks.