Dr. Gouin's Bay Gardener

On Bay Lawns, Weed Killers a No-No
The truth about weed-and-feed fertilizers

If you live near the Bay, you should not be using weed killers. Matter of fact, weed killers for lawns should be outlawed. Not only are they unnecessary and expensive, they contribute to the pollution of the Bay.

Why, then are they used? We’ve been brainwashed. Radio and television advertisers want you to believe that it is impossible to grow a lush, weed-free lawn without weed-and-feed fertilizers.

Working with herbicides almost continuously since 1958, I have respect for them and their responsible use. The application of weed-and-feed fertilizers is an irresponsible use of both herbicides and fertilizers.

Here’s the real story.

The combination of these materials is bad for several reasons. The time to apply a pre-emergent fertilizer to control crab grass is within two to three weeks following petal drop of forsythia in the Bay area. Applying weed-and-feed fertilizer earlier than that means that by the time the crabgrass starts to germinate, the pre-emergent herbicide will have become ineffective.

Applying a fertilizer to a bluegrass or fescue lawn this late in the spring means that you will be promoting soft succulent grass growth that will be susceptible to disease. Then you will have to purchase a fungicide to control the diseases you caused by applying the fertilizer too late in the spring. The same is true when applying weed-and-feed fertilizers to control dandelions and other broadleaf weeds.

If only a few weeds are growing in your a lawn, why apply a weed-and-feed fertilizer over the entire lawn? I have yet to see a decent lawn that needs a weed-and-feed fertilizer treatment.

If the lawn is nothing but weeds, it is time to renovate the lawn and start over again in August or September. No amount of weed-and-feed fertilizer can reclaim a neglected lawn.

Professor Emeritus Francis Gouin retired from the University of Maryland, where he was the state’s extension specialist in ornamental horticulture. Follow his column of practical gardening and plant advice every week, only in Bay Weekly. Ask Dr. Gouin your questions at [email protected].