What do you think is going on with my tomato plants. They've been in the garden for 3 weeks. They are very healthy and have been growing well but have just started showing discoloration on some leaves.

Are the spots grainy? Do they brush off? Or sunken? Like dry spots?

They are not getting enough sun and water. I planted mine in mid-May and look like small trees.
They are about 30" tall and are producing flowers and even fruit. I water every second or third day and they are in full sun.
I have not fertilized them as of yet.

Warmth
Sun
Water
Those are the keys 🔑

We're getting there Bill.

On the other hand, could they have been exposed to too much sun too quickly? Were they gradually hardened off from a more protected environment like a greenhouse? The small plant (basil?) at the bottom of the picture looks to have some possible sunburn.

Have you checked for pests?

What I find odd is that in the top picture the white seems to be following the veins.