Im not sure what it could be. Its showing on almost all of my palnts. Any help would be great. They have been in veg for about 2 to 2 1/2 months. I know thats a bit long im waiting on tents to arrive for flower. Im using a soil blend. Peat, compost, bone meal, blood meal, ect. Here is what im feeding them. Any addictional info needed just ask.
Check the white spots on the leaves for movement. edit prob sand tho. How moist is your soil under the sand?
Dry. Im watering now. I let the first inch or two dry before i water. I had a fungus gnat problem so thats the reason foor the thin half inch layer of cleaned all purpoae sand. I just put it on a few days ago. Therea no movement. Ive already checked for mites. No sign of them.
Looks like Phos but Im not familiar with your feed or why. Maybe your pH is off? the 6.5 on the board is your water I assume?
am no expert but looks like you have multiple issues going on there. i think i would start by removing all the dead/dying stuff and including cal-mag in the feed schedule since it corrects and prevents common deficiencies. also take a look here for other things that could be going on: Plant Doctor - Diagnose Your Plants! | Grow Weed Easy Good luck!
I thought that or mag but im using a good bit of both. My water is phed to about 6.5 and runoff ia aroind 6.4 to 6.6