To use Preen weed preventer, sprinkle the product onto the soil or mulch around cultivated plant seedlings. Apply the product while the soil is dry, and water the soil to activate the weed preventer.
The Preen website recommends applying Preen at the beginning of the growing season, when the plants you wish to cultivate are just starting to sprout. For maximum efficacy, apply Preen again in the middle of the growing season.
Use about 1 ounce of Preen per 10 square feet of garden space. Avoid allowing the weed protector to come into contact with your plants, as contact with the crystals may cause damage to leaves.