Those wood ashes from winter are not good for New Mexico gardens

by Curtis Smith, PhD, NMSU Extension Horticulture Specialist

Q. We live in Northern New Mexico and heat our house with wood, everything from willows to cottonwood to juniper to pinon and scrap lumber. We end up with lots of ash that I have been taking to the dump. We are completely organic and make our own compost from vegetable scraps, grass clippings, manure and straw. Can we use the ash in any way in our gardens. We have flowers, vegetables and fruit trees.

Hamilton B.
Arroyo Seco, NM

A. I understand your desire to put the wood ashes to good use, but wood ashes are one thing that we must recommend that you do not put into your garden. Ashes are beneficial when applied to soils in regions with high precipitation because the minerals in the ashes replace those leached away by the rains. I checked with Dr. Robert Flynn, NMSU Extension Agronomist, who is familiar with soils in all parts of New Mexico. He agreed that you should not apply the ashes to the landscape or garden. Most New Mexico soils are calcareous (high in calcium and other minerals) as a result of our arid environment. The minerals have not leached away in rains like those in the soils in eastern parts of the U.S. and soils in other regions with much more precipitation than we experience. Adding ashes adds more mineral salts to a soil that already has too many mineral salts. This would create problems for most garden and landscape plants. (continued at SW Yard and Garden column January 30, 2010)