Caliche Soil

I moved here from the Midwest. My neighbor explained that the reason I had trouble with my garden this year is that my soil is "caliche" soil. What is caliche soil? -Artesia (Eddy County)

Caliche is a term used often in New Mexico when speaking of soil. I think some people just mean the soil is very calcareous; that is, the soil contains a high level of calcium and has a high pH (is alkaline). Others think of caliche as a layer of rock (limestone) at some level below the surface of the soil.

I spoke to Dr. Robert Flynn, NMSU Extension Agronomist, about this, and he gave me some specific definitions which are important for gardeners to understand their soil. Caliche is defined as an amorphous (non-crystalline) mass of calcium carbonate (limestone) mixed with clay. The cement-like layer below the soil surface that is often called caliche is termed a "petrocalcic horizon" by soil scientists.

Many New Mexico gardeners will find that their usable soil depth is affected by an impermeable petrocalcic horizon as some depth below the soil surface. This affects drainage and can provide a source of calcium to thwart efforts to alter pH. This will also influence shrubs, trees, and other deeply rooted plants.

In order to learn the specific soil conditions influencing your garden, it is wise to send a soil sample to a soil-testing laboratory. This will provide information about soil physical and chemical characteristics allowing proper management of the soil.

Growing Culinary Herbs

I want to grow some culinary herbs on my windowsill during the winter. What should I do? -Taos (Taos County)

You should carefully choose the plants you will grow based on the size and location of the windowsill and the herbs that you will find useful.

Chives and bunching onions are easy to grow on a windowsill. Only a little of these herbs goes a long ways in cooking, but that is true of most herbs. They will do best in a south-facing window, but east-facing or west-facing will also work.

I have successfully grown basil through the winter in a south-facing window, though many books say that they don't make good windowsill plants. Rosemary, thyme, and many other common herbs may also be grown in a windowsill.

Carefully inspect the plants for insect infestation before bringing the plants indoors. It is a good idea to grow them outside a while after purchasing the plants to allow insect eggs to hatch before the plants are brought indoors. Watch for any symptoms of disease. Insects and diseases are much easier to treat outside, especially if chemical pesticides are needed. Be careful to choose pest control products that will not leave a residue on the leaves that you will be eating later in the winter. It is also possible to start many herbs from seed, but don't let plants brought in from outdoors infest them.

Once the plants are indoors, water carefully. As the weather changes and the furnace runs more, the plants will dry more rapidly.

Windowsill herbs are an easy way to continue gardening in the winter and to enhance the flavor of your meals. Happy winter gardening.

Please join us on Southwest Yard & Garden, a weekly garden program made for gardeners in the Southwest, broadcast on KRWG-Las Cruces on Saturdays at 11:30 a.m., Tuesdays at 6:30 p.m. and Thursdays at 1:00 p.m.; KENW-Portales on Saturdays at 10:00 a.m.; and KNME-Albuquerque on Saturdays at 12:00 noon, and Fridays at 2:30 p.m.

Send gardening questions to Southwest Yard and Garden, Attn: Dr. Marisa Thompson at desertblooms@nmsu.edu or at https://www.facebook.com/DesertBloomsNM/. Please include your county Extension Agent (aces.nmsu.edu/county) and your county of residence with your question!

For more gardening information, visit the NMSU Extension Horticulture page: desertblooms@nmsu.edu.

Marisa Y. Thompson, PhD, is the Extension Horticulture Specialist, in the Department of Extension Plant Sciences at the New Mexico State University Los Lunas Agricultural Science Center, office: 505-865-7340, ext. 113.