Whats on the bottom of my leaves?

[Bowman10117]

I have some peppers iv been growing for a bit to put outside next month, but some have this weird stuff under their leaves that will not come off. Im not sure what it is but its mainly affecting my purple cayennes. Heres a link to some picks of the leaves. https://www.dropbox.com/sc/9xqbwv79g307xdj/AAA29GT59bNgafLqHl3t0d8na

 

[Bhuter]

That's edema. It's cause by overwatering and/or high humidity. I'd say cut back on the watering and add a fan, if you haven't. What's there now won't go away, you just have to prevent it on future leaves.

 

[Bowman10117]

Most of my plants are half soil and half hydroponic. Could the hydro nutes be doing this?

 

[Bhuter]

I've never grown hydro, so I really don't know. Hopefully somebody else could chime in.

 

[Bowman10117]

Alright thanks very much though.