lessen your lighting period later in the flowering period to lessen fox tailing. think about how the light is outside. i get these are autoflower plants but they still hold on to that photo specific lighting needs in a certain sort of way. i flipped a auto gorilla glue from 12 12 to 16 and it started stretching again and fox tailed like crazy. thought i could get away with it... boy was i wrong lmao. 20 hrs is great for vegging especially if you have raised co2 levels. but late game id back the lighting off to keep it from stretching out again. also some plants really appriciate it as i said yes .. . these are auto flower but they still retain some sort of photo specific "ness"
your grow looks great try it out, it could be one of those "missing pieces" we all find along the way.
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