I'm having trouble diagnosing what's going on with my Zukes. I've got two plants about 1 month old each in large pots. One was a little bigger than the other but both seemed to be doing very well. Int he last two days, the smaller one started having pale leaves with brown/yellow edges. Today, the bigger one developed yellowish edges and pale sections within the leaves. I don't believe this is overwatering. Thanks much!

Smaller guy:


Big guy:

Looks like they have powdery mildew starting first off, that'll kill em fast. Use copper fungicide (or you can try one of the other ones, but I don't have experience with those working) now.

Otherwise, yes probably overwatering, way too little nitrogen, way too little sunlight. Looks like it's in a pot on a doorstep or something, absolutely needs to be in a full sun spot to be healthy.

Agreed. Yellow leaves with green veining is chlorosis, and that's from overwatering. Now, underwatering can cause yellow leaves too, but not with veining. Nutrient deficiency (esp iron) can do it too. Squash can tolerate poor sunlight, but their productivity will be way down.

Appreciate the help guys. I'll fertilize and move them into a sunnier spot. I'm somewhat doubtful that this is a nutrient deficiency or overwatering since I've kept the same regiment and it's only getting hotter/ plants are getting larger, and the decline of these plants has happened so fast.

I've seen powdery mildew on zukes before and this appears different from my last experience.