Water in products 1/2 inch or more (up to 3″). If the soil is already saturated, water in 1/4 inch. Rain is best. Must water in within 24 hrs. I have rain barrels and use my rain water for watering my pots and gardens. It saves on the utility bills and is really an environmentally friendly idea. Additionally, you do not want to let the product sit on plant leaves for too long in order to protect transpiration. These products work on the ground and in the soil.