What Are These Spots?

400w HPS in cool tube 24/7
Great air circulation.
75*F 35% Rh
Ph regulated by lime.
Potting soil/perlite great drainage.
Ferts given upon necessity only.


I think it needs some Mg, so I gave it calmag and a little epsom yesterday. Fed it a 18-14-12, one of the nutes contains molybdenum zinc calcium iron and a few others.

I'm really not sure about the spots.







Any input would be appreciated.

Either give calmag or Epsom, not both. Too much Mg can lock out Ca. Don't look for the existing spots to go away, rather watch the new growth for signs of it continuing.

hey dude what you have my friend is spider mites.. get a magnifying glass or loop n look on the bottoms and you will see lil black spots there the spiders the white spots are the eggs.. neem oil will work just make sure you do it every 4-7 days to kill any eggs that might hatch..

Thats what I thought at first, and yes, the first thing I did was got my dope scope and started looking for bugs, or spiders, aphids, webs or any other telltale signs of a pest. I was surprised not to have seen any. No bite marks or droppings either, these spots are yellowing from the inside out.

I was thinking Calcium deficient, but not lockout, really good point. Should I just ride it out? The Ca/MG thing makes sense too, as I'm seeing light signs in a couple other plants.

My first guess was Ca but it's just that, a guess.

Anyway do a Google image search for "Calcium Deficiency Cannabis" and you will see a lot of pics that look like your plant.

I add CalMag every watering and it has never caused me a problem. The CalMag I mean.

I first thought spidermite too, but obv not as you checked.... i'd lean more to nute burn than anything else (for the spotted leaves), as other poster said, keep an eye on new growth, the spots will not go away now. I'd be careful adding anything in large doses as your in soil. I grow in coco... but can see a slight yellow tinge in your new growth - epsom salts would be worth a try for sure, looks like slight MG def to me too...