February 1996

Q. This past summer, bugs ate the leaves off my turnips, squash, rutabagas, etc., in a short period of time while I was away from home. I had applied wood ashes mixed with water and dishwashing soap. What should I use rather than a toxic chemical?

Also, should I transplant evergreens in the winter or early spring? When is the best time for transplanting? I also have several locust seedlings to move. I have a wood-burning stove. Can I, or should I, spread the ashes on my garden or lawn? – William Erickson, New Richmond, Ind.

A. Insecticidal soap must be applied to the insect to be effective, since it works by breaking down the external coating of the pest. It has no effect on insects that eat it, so if you sprayed your plants, left town, and then the insects arrived, they could eat your soapy plants in peace. You need to be more diligent. Also, insecticidal soaps work best on soft-bodied insects and aren’t likely to be as effective on beetles, which have a hard shell. Identification of the pest is always the first step in control. Once you know the pest, you could choose another organic pesticide with a different formulation. They are available from garden centers, hardware stores and mail-order companies, including Gardens Alive, (812) 537-8650, or Ringer (612) 941-4180.

Wait until early spring to accomplish the transplanting. You need to make sure the roots are in contact with soil and there are no air pockets. That’s tricky when the ground is frozen. Make sure you get the job done in early spring, not late, and water regularly throughout summer and fall.

Wood ash has some fertilizer value, but it’s chock full of liming material, which increases soil alkalinity. Nutrients are most readily available to plants when the soil is slightly acidic. As soil alkalinity increases and pH rises above 7.0, many nutrients become tied to the soil and less available to plants. A little wood ash can be good, but it’s easy to overdo it. If your soil is slightly acidic, an application of 20 pounds per 1,000 square feet annually should not hurt. However, if your soil is neutral or alkaline (pH greater than 7.0), find another way to dispose of the ashes. If you don’t know the pH of your soil, have it tested. Wood ash should never be used on acid-loving plants like rhododendrons or blueberries and, since it is highly caustic, it can cause plant damage if applied directly to the plants.

Note to my readers:

On occasion, you’ll read in this column, “For further information, contact your county office of the Purdue University Cooperative Extension Service and request publication ‘XXX.'” I’m not being lazy! Some topics require four pages of explanation, not four sentences, and that information is all well-presented in Extension publications. The Extension service has a terrific list of publications that cover many of your garden questions in detail. When I recommend one, it’s worth making the call! You can probably find your Extension office listed in the white pages under your county name. You also can call to get a copy of all the publications available. (Ask for HO-179, “Home, Yard and Garden Publications.) Topics include specific fruits, nuts, ornamentals, vegetables and houseplants, landscaping, diseases, insects, lawns, and all kinds of miscellaneous things like compost, starting seeds indoors, and garden calendars. I urge you to utilize this resource, but don’t quit writing!

Share This Article
Disclaimer: Reference to products is not intended to be an endorsement to the exclusion of others which may have similar uses. Any person using products listed in these articles assumes full responsibility for their use in accordance with current directions of the manufacturer.
Indiana Yard and Garden – Purdue Consumer Horticulture - Horticulture & Landscape Architecture, 625 Agriculture Mall, West Lafayette, IN 47907

© 2018 Purdue University | An equal access/equal opportunity university | Copyright Complaints | Maintained by Indiana Yard and Garden – Purdue Consumer Horticulture

If you have trouble accessing this page because of a disability, please contact Indiana Yard and Garden – Purdue Consumer Horticulture at homehort@purdue.edu.