Just check for the white dots moveing slow on the under side of the leaf. Those pics are not really good enough to see. But it looms like you just get whmater on the plants when you water them.
You are correct in the assumption that you have spider mites. Too bad - sorry. Solution here - Spider Mites J
I already gave you the answer. Click on the link and read, and then follow instructions explicitly. J
2 tbs neem oil 1 tbs biodegradable soap into 32oz spray solution ontop and below all leaves repeat this once or twice a week for 2-4 weeks and that should rid you of these mites. But do not spray after nugs have started to form. Sent from my SM-G920P using Tapatalk