CUISINE & CULTURE
Cold weather and fireplaces go together. A bright, warm wood fire is a great way to spend a cold winter evening and after the fire burns down, the ashes are left behind. Now what to do with the ashes.
Many garden websites and online sources extol the virtues of wood ash in the garden—but consider the source of the websites that encourage use of wood ash. Many of the websites originate in northern or eastern regions of the country that have acidic soils.
The advantage and good side of wood ash. Nutrient content of the ash reflects the nutrients of the tree before it was cut into logs. Most sources of wood ash has the minerals calcium and magnesium; minerals phosphorous and potassium most predominant nutrients.
On every bag of fertilizer is a list of the minerals present. Often the name ‘potash’ is listed. Potash is the bioavailable form of potassium. It came to be used in agriculture because the term pot-ash is an abridgment of wood ash that was collected in metal pots, hence became potash.
The nutrient content of hardwoods like oak is superior to that of softwoods like pine. Minerals in the ash are leached into the soil.
The disadvantage and downside of wood ash. Wood ash is alkaline and is used as an amendment to reduce acidity of soils. West Texas soils already have a pH higher than neutral, some with a pH as high as 7.5 to 7.8. The last thing our soils need is another source of alkalinity.
Most vegetables have an optimum pH range of 6.8 to 7.0. Adding wood ash raises the pH to a range that may be a detriment to the optimum growth and development of a crop plant.
What about charcoal? Charcoal has similar properties of wood ash. When the charcoal briquets have been burned it is known as biochar. It is comparable to wood ash in that it used to raise the pH of soils. One advantage of biochar is that after the briquets have burned there are often traces of briquets that have not burned down to ash. The little pieces add some aeration to the soil.
Anecdotal benefit of wood ash. Some gardeners circle the base of fruit trees with wood ash to discourage bores, which may or may not deter pests.
Ellen Peffley Harp, a retired professor of horticulture at Texas Tech University, writes about gardening for several Texas newspapers
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