Water sometimes beads up on the soil surface, refusing to penetrate and soak in to where plant roots need it most. Sandy soil, poorly tilled soil and soil that contains organic matter but has been allowed to dry out completely are most likely to repel water. A soil-wetting agent, also called a surfactant, coats the soil particles on the molecular level so the water can infiltrate the garden bed. Although commercial wetting agents are available for both outdoor and indoor use, you can make your own temporary solution to combat a short-term moisture issue.
Garden Bed Application
Fill a hose-end spray applicator with liquid dish soap, but avoid dish detergents. Screw the sprayer onto the end of your garden hose.
Adjust the application rate dial on the sprayer to 5 tablespoons per gallon. This will mix 5 tablespoons of dish soap with every 1 gallon of water that exits the sprayer nozzle.
Water the soil with the soap and water mixture. Apply the mixture directly to the soil and avoid spraying any plants when possible. Thoroughly saturate the soil so it feels moist to at least a 4-inch depth. Monitor the soap level in the sprayer bottle and refill it as necessary.
Rinse any plants or grasses in or near the soil bed with clear water immediately after application to remove any soap residue from the foliage. Wait two hours before applying any chemical pesticides, fertilizers or other lawn or plant treatments.
Moister Potting Soil
Fill a 1-gallon watering can with water. Add one or two drops of liquid dish soap to the can.
Mix the soap and water together with a spoon or stick, stirring slowly to avoid suds.
Water the soil in the pot with the mixture until the excess water begins to drain from the bottom of the pot. If you are moistening new soil in preparation of potting. Stir the soil and water together to ensure the soil is completely saturated with the mixture.
Allow the soil to drain for 30 minutes. Empty the collected water from the drip tray beneath the pot.