Wetting agents are designed to increase the water retention of your garden. Unlike fertilisers or organic compost designed for the same purpose, a wetting agent does not increase a soil's ability to trap water. Wetting agents actually alter the garden water's physical composition, lowering the surface tension of the water. Wetting agents are ideal for sandy soils with too much drainage, and you can make your own at home.
Measure 56.7gr of pure soap. Pure soap is a sodium salt derived from carboxylate, and it works as a wetting agent. Only use pure salt soap, as scented soap powders react poorly with your garden plants.
Mix pure soap with 1 gallon of water.
Stir the liquid for about five minutes until all the salt has dissolved. The resulting water is your wetting agent, and you can apply it directly to your garden.
Water your garden with normal water for the next two or three days.
Scoop away the topsoil and check to see that water is penetrating your garden. After two or three days of normal watering, you may notice the soil's water retention depleting again. Apply more wetting agent whenever you notice the soil becoming dry. A homemade soil-wetting agent only increases water retention for a few days, while commercial products last more than a week.