Yellowing w/ brown spots on leaves! 4 week old MK

Greetings cultivators,

Im facing a problem with one of my baby MK's, she's (hopefully) kind of showing some diseased symptoms, yellowing on the lower plants, brown spots allover, and the steam seems to be lagging behind her twin sister, and another plant, it's a bit weak and thin. The plant's height is average, yet not as many stems and leaves.

I've added a picture of some leaves to get a better judgment passed at me, please dont be greedy on your advice.

Cheers.

mine are doing the same and its mites, you can barely see them on the underside of the leave, they are 10 times smaller then a pen point so look good

hmmm, looks like some kind of deficency...me say, flush her out, chck pH, and feed =)

phosphorus deficiency, in the beginning stage. add more phosphorus

try this its a great guide

Thanks for the comments guys, mixed views here don't know which is more accurate. I've checked the chart, it claims a pottasium/phosphorus deficiency. at the same time, I can't really cut out the spider mite point of view, as I have been noticing a couple of leaves being eaten from the top parts. Question is, how can I check for spider mites? AND how to completely destroy those little bastards.

spider mites feed on the undersides of leaves - hold a leaf over a plain sheet of white paper and thump the top of a leaf a few times - now look at the paper very carefully - if you see little critters ( they look like tiny dots on the paper) start moving you can count on mites - get a 10x or so scope or single lens and you will be able to see them easily - good luck

any homemade ways to destroy these bastards.. trying to find neem oil to protect the plants, but I just used Earth Options by Raid, not sure how good it is but Im desperate, Don't wanna move those babies to flowering when they're looking this bad.