Bright Yellow Spots?

[WTotal]

What could this be?

According to the USDA Plant Hardiness Zone Map, I live in Zone 10a. Also, I fertilized with bone meal about a week ago. I've been giving my plants about a gallon of water everyday for the past week, since the soil always feels dry.

[PaulF]

This could be the beginnings of early blight. I would remove those leaves. Early blight can be controlled with a fungicide application. The yellowing will soon turn brown and the leaves get crispy. It starts at the bottom of the plant and works up. EB is a soil borne fungus and begins with soil splashing up onto the leaves. It looks like you have mulch under the plants which is good. If these are bottom leaves EB may be the culprit.

Only a guess on my part. You may have to wait a while to see what happens next.

[jemsister]

I agree that it could be blight. The pic on the bottom has a splashed-on look to it, which throws me. I've not seen it look quite like that. But the other pics definitely look like EB to me.