Is soil to blame for water soaking?
There are many reasons why water may not soak into your soil quickly. Many people blame it on clay soil. In the Antelope Valley clay soil is very uncommon. In the several million acres of soil in the Antelope Valley, less than 50 thousand acres are classified as clay soil. Clay soils have small pore spaces, the space between the soil particles, and the water takes longer to be absorbed. A lot of people feel that they have clay soils, but most have very sandy soils.
The problem is usually compaction or poor soil structure. A good test for poor water absorption is to dig a small depression in the soil and add water. If the soil digs easier after the water, the problem is compaction or poor soil structure. If it is harder to dig and sticks to the shovel, the problem could be clay soil.
The most common reason is soil compaction. Soil compaction in the Antelope Valley is normally caused when your home was built. The lot your home was built on is packed to prevent your home from settling and cracking.
A typical soil is about 50% solid matter and 50% air or water space between the particles. As this space fills with water it pushes the particles further apart, which can cause cracks in concrete or your home — very similar to a sponge swelling when wet and shrinking when dry. After the soil is compacted to build a house, your soil is around 85% solid with only 15% air or water space. This makes it very hard for your soil to absorb water.
Rototilling your garden and landscape is the only cure for compacted soil. If you are installing a new landscape, the entire landscape should be rototilled as deep as possible.
Another problem similar to compaction is poor soil structure. Poor soil structure is where the three soil particles — sand, silt and clay — separate in the soil. Under ideal conditions these three particles stick together and form a soil structure called a ped. If enough peds stick together you form clods. If the particles do not stick together, and separate, clay comes to the surface, just below the clay is the silt and everything below that is sand. With a soil surface of clay, water does not penetrate the soil very quickly and water has a difficult time moving through different soil layers.
Organic matter is the key to making good structure. The organic matter ties the different soil particles together to form peds. Poor soil structure can be improved with the addition of organic matter. Some improvement should be seen in a year, but it will take several years for any major soil structure improvement.
Another problem with poor soil structure could be too much sodium in the soil. Excess sodium in the soil destroys the ability of organic matter to hold the soil particles together. Even with a lot of organic matter in the soil, if there is excess sodium, you will still have a soil structure problem. If your soil problem is excess sodium, you can cure the problem by adding gypsum. Gypsum replaces the sodium in the soil with calcium leaving the excess sodium to be leached out of your soil. Leaching is adding a lot of water to wash the sodium out of the root zone.
Another problem that causes poor water penetration is impermeable layers in your soil. Impervious layers can be hardpans or calcium layers in your soil preventing the water from soaking through. The most common is a caliche or limestone layer in the soil.
The only cure for this problem is to punch or drill holes through the impermeable layers. Over time, and with water these holes should increase in size and water movement will improve. This may seem simple and in some cases it is, but in some cases it will be very difficult. At some of the dry lakes and old riverbeds and in the surrounding neighborhood, the limestone layer could be as thick as 25 feet.
As for the many products that say they increase water penetration and movement, read the label. First determine what is causing your water problem. If it is just compacted soil, none of the products are going to help as much as a deep rototilling of the soil. Gypsum has always been the cure-all, but it works only if the soil has excess sodium.
As for many of the products, they contain glycerin, which causes the water not to stick to surfaces or lose its tension. They let the water run through the soil without being affected by the soil particles. Yes, it makes the water penetrate your soil quickly, but does nothing to solve the problem.
Without hiring an expert to diagnose the problem, adding several inches of organic matter and rototilling it into your soil is the best bet. Adding gypsum might help — not likely — but the cost of adding could be good insurance for a reasonable cost if you are already rototilling.