Your best line of defense against powdery mildew. Intended for greenhouse use, the vaporizer is a great method for combating powdery mildew in the greenhouse or hobby greenhouse setting> Each vaporizer will treat 260-360 sq.ft. It is suggested that the vaporizer be used as a preventative measure and should be used for half an hour each day or until tip burn is experienced - then reduce time. For example, if the vaporizer is on for 10 minutes a day and tip burn is experienced, then reduce time to 7-8 minutes or until tip burn does not occur Again, this product is very effective. You can trust the quality of Green Planet's Sulphur Vaporizer Features