You just saved me. I have a foxtail problem and I was supposed to Harvest today (Makes sense, I should have stopped feeding her 2 weeks ago).... I was thinking I was gonna feed her some more and maybe that will help lol. Newbie thinking more feed was gonna solve the problem. Thank You.
In my experience it's not ever been feed related. It's always been caused by light intensity, heat or just the genetics of the plant.
Just don't let the foxtailing keep you from harvesting when the majority of the plant is ready.
Good luck friend!