New Mexico’s soils typically lack the organic matter necessary to provide sufficient plant nutrients and water retention. Native plants tend to need less organic matter than adapted plants, but most plants benefit from the addition of some organic matter, such as compost, into the soil.
Compost helps sandy soils retain water and helps clay-dominated soils drain faster. When water mixes with compost in soil, the resultant carbonic acid dissolves the 18 essential elements typically found in compost so that plant roots can more easily take up these nutrients. Compost also aerates the soil so that plant roots can maintain their optimal moisture content. In these improved conditions, the insects, microorganisms and mycelium found in healthy soil can thrive, so plants can establish themselves quickly in the landscape.
Perhaps you have already been diligently making compost with your kitchen scraps and yard waste in a convenient, shaded and wind-protected corner of your garden. Maybe you’ve even added rabbit, chicken or horse manure, or some other source of nitrogen to your compost pile. Chances are, however, that you may need to either import compost (to mix into your existing soil) or bring in some premixed topsoil.
But don’t give plants (especially native plants and other plants that like “lean” soil) too much of a good thing. Roots pampered by too-rich soil are likely to be stunted when they grow to the outer edges of the imported soil and hit the hard edge of existing native soil. Those pampered plants will not be as hardy, particularly in drought or precipitationonly conditions. Smart roof-reliant landscapers understand that the best time to complete the soil-building part of the project occurs when cistern excavation equipment is onsite, particularly when installing a new landscape. With impressive efficiency, a backhoe can often handle much of the excavation, importation and mixing processes of soil improvement. Heavy equipment can also efficiently remove layers of cement-like caliche, which sometimes plague New Mexico’s soil.
If it is not practical to use heavy excavation equipment to mix compost into your soil, consider renting a jackhammer to loosen up hard soil. Rototillers are also helpful when mixing compost and other organic matter into the soil.