Powdery Mildew or Edema?

I have already posted about my plants (Jalapenos) not doing well, but now I discovered that I must have a massive problem with either edema, or powdery mildew. The thing is, I can't really say which one, even when I look at the stuff with a microscope.
 
There is this white to yellowish substance ONLY on the underside of (many) leaves. The substance feels "crystal-y" and cannot be wiped off.
 
The leaves which are affected feel thick, stiff, leathery and dry and they curl up on the sides. They then get yellow, with reddish veins, until they fall off. (I apologize since I already posted about this problem yesterday, but now since I found these "crystals" it's clear it must be either edema or PM, this is why I made this thread).
 
This time I provided pics which clearly show what the problem is.
 
Unfortunately, last year I had the same thing going on, which essentially killed all my plants. So I am panicking now.
 
Yesterday I sprayed with a baking soda, soap and a few drops neem oil solution since I came across that this might work against PM. (I don't have a fungicide here and I also don't think I can get one locally, would have to order online).
 

 

 

Right now, I need to determine whether this is edema or PM first.
 
(Here are the pics again on the imgur album: https://imgur.com/a/XUV6nSv )
 
Thank you!
 
 

That does not look like powdery mildew to me. Do you live in an area that grows grapes? Asking because powdery mildew is typically associated with grape growing regions.
 
It looks like the plants are inside. Do you have a fan moving air? 

Edema...
Cause over watering


Powdery mildew is a white mold easy wiped away by hand. I do not see that at all.

Plants look in need of bigger pots.

Yes absolutely cannot be wiped, that would be a BIG indication it's not PM.
 
Yes, I am aware the pots are too small, but in the past it worked at this size. Currently it is very hot (yes, the plants are in a green house, RH is usually 55%). The pots do however get bone-dry pretty much every day and I water only when the plants are basically wilting from being dry. But I can see that it is possibly the frequency of watering (small pot = NEED TO water often) that ultimately is the problem, so you are very likely correct saying they would need larger pots.
 
I am just glad we can exclude PM so I can work on a solution rather than wondering what's going on. (There is a small fan in the GH and there is also lots of openings in the GH for air flow)