By JoAnne Skelly
Soil is a living substance. It's not just dirt! Dirt comes out of a vacuum cleaner and is not suitable for growing plants. Many people take their soil for granted, but experienced gardeners know that healthy soil helps to produce healthy, happy plants. What factors contribute to a healthy soil?
Plants receive nutrients, oxygen, water and support from soil. Various soil characteristics influence the success of plants, such as the amount of clay or sand in the soil, the chemical content, the amount of organic matter present, the pH level, and the organisms that live in the soil. Nevada soil usually isn't fertile or loose, but it can be improved, particularly with the addition of organic matter.
Organic matter is the decayed remains of once-living plants, animals and soil organisms. It starts out as raw material, such as dead leaves and grass clippings, and then decomposes into rich, black material, called humus. Mixed into the soil as an amendment, this decayed material feeds beneficial microorganisms, breaks down into useable nutrients, and holds water in sandy soils. It loosens up clay soils, allowing better air circulation and drainage. Loose soil provides ideal conditions for strong root growth and high yields. Added as a mulch layer on top of the soil, organic matter can smother weeds, hold moisture, mitigate soil temperature fluctuations, and slowly release nutrients into the soil.
Good soil preparation before planting time is essential for a productive garden and great-looking plants. However, too much tilling or tilling when the soil is too wet can be bad. If the soil stays in a firm ball when you squeeze it, it's too wet to work. Fall can be a great time for soil preparation, because any organic matter, such as compost, humus, grass clippings, leaves, or straw, will have time to decay before spring planting. The freeze-thaw cycle of winter will help to break up clods.
Nevada soils benefit from the addition of a 2- to 3-inch layer of organic matter in the fall. The same amount can be added again in the spring before planting. Sandy soils need a lot of organic matter, both fast- and slow-digesting types. Manures, grass clippings, and compost break down quickly. Sawdust, wood chips, or straw rot slowly. Heavy clay soils can become compacted naturally. Adding organic matter will break up the compaction to allow air and soil movement, as well as root penetration.
Successful gardeners pay attention to the soil now and find that Nevada soil is worth the toil when flower and vegetable season arrives.
For more information, e-mail skellyj@unce.unr.edu or call me at 887-2252. You can "Ask a Master Gardener" by e-mailing mastergardeners@unce.unr.edu or call your local University of Nevada Cooperative Extension office. Check out many useful horticulture publications at www.unce.unr.edu.
• JoAnne Skelly is the Carson City/Storey County Extension educator for University of Nevada Cooperative Extension.