Ken from Bixby, Ok writes
The Phos-Chek Long Term Fire Retardant product label states that it will last "for the entire fire season so long as the weather remains dry. Rainfall of 1/4 in. or more will wash Phos-Chek off treated vegetation." If grass is cut or if you receive more than 1/4 in. of rainfall, you would need to reapply.
Answer last updated on: 04/30/2018