Answer: Wood ashes are a source of potash and are also alkaline. To use them as a fertilizer requires some care; the potash leaches away quickly and so is not of lasting value, particularly in container plantings amd they can have an adverse effect on the soil pH. You should be careful not to allow them to contact germinating seeds or immature plant roots or acid-loving plants. Usually, wood ashes are used as a side dressing or as a component in a blend of fertilizing materials to be added to the garden. A common application rate is 5 to 10 pounds per 100 square feet, but in order to know how much (if any) you need to add it's a good idea to run some basic soil tests first. Your County Extension (599-6162) can help you with the tests and with interpreting the results.
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