Severe leaf curl

Anyone know what causes this?? Every single grow no matter what strain
I thought maybe it was magnesium deficiency so have been adding some canna mono 1ml/L since the start of this grow but doesn’t seem to make any difference

These leaves will eventually die but I’m only 6 weeks into flower

what is the temp in your tent? medium you are growing in, lights? hard to diag a problem with little info

stalebiscuit said:

what is the temp in your tent? medium you are growing in, lights? hard to diag a problem with little info

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temps 27-28 C
growing in soil under COBs

I think it could be Light Burn - I do have my plants fairly close to the LEDs