Putting Ashes on Gardens Not Always Good Idea

Putting Ashes on Gardens Not Always Good Idea

Soil in much of Kansas not acidic enough to need ashes.

For generations, gardeners have been adding wood ashes to their vegetable plots as a fertilizer and soil amendment. For them, it´s been a second use for the wood burned in cooking and staying warm.

However, in much of Kansas, the soil profile isn't right for adding ashes to work well said Jake Weber, horticulturist with Kansas State University Research and Extension.

Adding ashes works best, he said, where the soil´s available levels of phosphate and potash are in low range. The soil also should be acidic enough to need a higher pH - i.e., be more alkaline.

"That´s much more likely in the northeastern United States than in the limestone-rich High Plains," Weber said. "To avoid problems, Plains residents should have their garden´s soil tested first, to determine the need for changing pH or adding nutrients."

The horticulturist provided these additional cautions for Kansans who feel compelled to recycle:

* Try to maintain a margin of safety by limiting your annual application rate to no more than 5 pounds of wood ash per 1,000 square feet.

* Stop wood ash applications when the soil´s pH reaches 7 or when its phosphate and potash levels climb into the very high range.

* Do your homework first. In addition to such landscape plants as the hydrangea, heather and azalea, many vegetables and fruits prefer slightly acidic soil - the opposite of what ashes create.

Weber said Colorado Extension has a good list of plants and their preferred pH levels. Links to the list´s groupings of houseplants, woody ornamentals, vegetables and fruits are available on-line at www.coopext.colostate.edu/TRA/PLANTS/acidlove.html.

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