This liquid non-toxic spray is like a natural anti-freeze that protects plants by enhancing both their natural "anti-freeze"-like properties and their ability to survive ice crystal damage. Natural materials are absorbed into the cells of plants and give them more tolerance to cold. Use Freez-Pruf to protect plants early in the season, then use it late in the season to extend your growing time. Spray on plants when temperatures are 50 F or higher. Coverage lasts up to 6 weeks before a reapplication is needed.