Are you growing in dirt?

You can try to flush them with just ph adjuster water 3 times the volume then back to your normal NPK nutrient.

What nutrients are you feeding them?

But to answer that last question. It can kill your plant quickly. There are a few other things it could be but you can't tell me the Ph so that is my best guess.
Zandor Reviewed by Zandor on . Small Problem The 1st set of leaves above the circle leaves are turning colors..and the 2nd set have some black spots on it..here is pics...any help? Rating: 5