Could be a number of things from pH problems to a deficiency. Is there wide or heat directly on those spots?
Give a little more info around the growing medium and pH, temps, etc. as per the sticky on how to ask for help. Then we can try to give a bit more relevant feedback
Hi ,
My plants are in a 4'x4' x6' tent, im using a leavingtons compost, the ph is 6, im using 900 watt led, the plants are 5 weeks old, the temp has been steady at 75f,i have a 6'' intake & extraction,the highest the humidity has been is 62%,although generally its about 50% mark. i water once every 3 days, if needed. i would appreciate any help .