Black spots?

What do black spots on the underside of the lower leafs? Is this mites?

Can you post a picture of the spots? Are they really tiny and moving around? Like slow-moving pepper?

oh dang man!! you might have spider mites, or eggs or the larvae, or some sort of fungus. But this sounds like mites to me, you better start hitting those things with azamax or something similar hard and ASAP before they explode!!!

As far as I can tell they are not moving. They look like they are either black scales or black spots growing inside the leaf. Any help would be greatly appreciated.

I also forget to mention that this is an outdoor grow.

Pretty sure you have mites. If you dont have any insecticide then use some sunlight dish soap, a drop in a spray bottle, soak the whole plant under leaves and all. Repeat this every other day. If you dont do anything and this is spider mites, they will spread pretty dam quick. When they spread rapidly, you know you have spider mites

Sounds like you have thrips, if it looks there are tiny scales on the leaves then it's thrips. Beneficial nematodes are a good way to get rid of the thrips because it attacks the larva in the soil. But if you are doing an outside grow it is probably a good idea just to use ben. nemo's anyway as a preventative.