Yup. Looks like nutrient burn, plus there's no perlite in the soil.

Double check application rate and frequency. a 20-20-20 fertilizer, at best, is an every other week strength. (or 1/2 strength, once a week) It's not a time release nutrient, is it?

Get some perlite or a potting mix that has perlite. It aerates the soil (lightens it up) and prevents soil compaction. Otherwise, you can end up with a muddy mess that suffocates the roots. Too late to add it now, but on your nest transplant...or future grows...your plants will appreciate the addition.
Rusty Trichome Reviewed by Rusty Trichome on . PLEASE HELP. First time grow . Please Help ME!!! Nute Burn ? N deficiency ? Over Watering ? PLEASE HELPPPP Ive added 20-20-20 nutes 3 days ago (a small dose), and it hasn't go any better, i didnt water since. Rating: 5