Soil is the foundation of our landscapes. Without good soil, plants won’t grow and thrive. Good soil has a mixture of sand, silt and clay, with plenty of organic matter and pore spaces. The pore spaces contain air and water and are the places where plant roots grow. These pore spaces are also where the biological component of our soil lives. Beyond earthworms, there is an amazing wealth of living creatures in our soil, from bacteria and fungi to nematodes and insects. All these creatures aid in making our soils productive by converting chemicals in the soil to forms plants can use as nutrients.
How can we keep the biological component of our soil happy and healthy, so they continue their important work? Like all creatures, they need food, water and shelter. Remember that the food, water and creatures in the soil live in the pore spaces. Avoiding compaction is imperative to maintain the pore spaces. Avoid working or walking on wet soil. Obviously, we want to move through our landscapes, so design travel paths in your landscape.
Is your soil already compacted? Adding organic matter can help improve the porosity of the soil. Organic matter will also improve the water-holding and the nutrient-holding capacity of your soil. Organic matter will feed some of the living creatures in your soil.
How can you add organic matter? Don’t add raw or uncomposted organic matter. It will continue to break down in the soil, consuming nutrients in the process instead of providing them to your plants. The best way to improve your soil is to add composted organic matter. Composting or aging breaks down the organic materials into stable forms that aid your soil. Composting also helps to reduce weed seeds, insect eggs and larva, and pathogens that may have been present in the raw organic materials.
Where can you get compost? You can make compost from household vegetable materials and garden plant debris. This is a great way to improve your soil and reduce your wastes. For more information on composting, read University of Nevada Cooperative Extension Factsheet FS-09-16, Composting Yard and Vegetable Wastes, http://www.unce.unr.edu/publications/files/nr/2009/fs0916.pdf.
Many garden centers also sell compost. Look carefully at the compost. It should be dark, crumbly, and earthy smelling. Avoid compost that smells bad or has visible chunks of plant materials or manures that have not broken down. Be cautious when purchasing top soil or fill dirt, as you’re likely to inherit a new set of problems unless you know the seller and the quality of materials.
Adding compost increases the nutrient-holding and water-holding capacity of your soil. Organic matter improves soil porosity, providing spaces for roots to grow. It also provides a home for the wealth of living creatures present in your soil. These creatures help convert the nutrients in the soil into forms that plants can use. Make them welcome in your soil by providing space for them to live and your plants will benefit.
Melody Hefner is the Urban IPM and Pesticide Safety Program Coordinator for the University of Nevada Cooperative Extension. Have a question about your soil or plants? Contact a master gardener at firstname.lastname@example.org.