Hashyanswered grow question 3 years ago I have trimmed roots in the past and had good results, I didn't trim lots away. After the 4th week I stop trimming them and let them fill the container. Also make sure the roots that get cut off don't end up in the res. The scissors have to be sterile. I have been advised against doing it. If you think they are causing a problem cutting an inch off prob won't make a difference, don't cut the tap root if that's in amongst them.