Never trim your roots. If you are root bound; Gently re pot into bigger pot.

Yellowing of leaves is normal as plant matures and is getting ready for harvest. during flower, about 1/2 way thru, we start to lower Nitrogen intake of plant, and this results in Yellowing of fan leaves. This shows us that the plant is using the dtored nutrient (Nitrogen) and thue\s the fan leaves yellow and fall off.