Keep the pots and soil covered so the roots don't bake,and keep the plant hydrated-
If it's over100 degrees(Az),a little too much water is better than not enough.
They don't tolerate water deprivation for very long when it's that hot out.
Don't drown them,but don't let them dry out,either.
Some of the best smoke I've had was grown in New Mexico. It can handle heat with plenty of water as already stated. Good herb grows in some very warm places.
Nothing wrong with foxtails-they smoke just fine...I'm guessing it's been hotter than hell in Az.?
It may just be the heat causing the foxtails...
I wouldn't harvest because of the foxtails ,unless there's some amber trichomes on them...