Good luck with this grow! GG4 loves to stretch during the first 3 weeks of flowering. I harvested one GG4 just over a month ago and have a second GG4 on the grow now.
@gr_andies, my advice is to keep her properly fed. If you look at my current GG4 grow, she's very hungry and I'm still increasing her weekly feeding (water + nutes). The longer this strain veg'd, then more she will stretch and the more food she will require.
@CanadianFillmore, thanks for the heads up, I was actually wondering about its stretch going into flower. I'm trying to train her low in anticipation of it. It's my first photo grow from seed 🌞 any advice is greatly appreciated, thanks _ happy growing!!