Folk remedies aren’t always best for garden

Now that it is spring, gardeners are beginning to think about how to improve their gardens, save money or make less work for themselves. The subject of folk remedies for garden problems always comes up in the discussions.

I read an interesting book on the subject this winter by Jeff Gillman titled “The Truth about Garden Remedies” (Timber Press, 2008). Gillman teaches horticulture at the University of Minnesota. In it he reviews the research on dozens of folk remedies commonly used by gardeners and explains why they do or don’t work. Here are a few I found interesting.

•Corn gluten meal is sold as an organic substitute to pre-emergent weed suppressants. The meal contains chemicals that suppress root growth in other plants, Gillman found that it works but it did so to varying degrees, depending on what part of the country it was used in. He also found that the meal needs to be applied to an area for two to three years to be effective. Even then, the gardener is still going to have to pull errant weeds. He recommends that a good mulch cover does a better job of controlling weeds in the short run.

•Another herbicide he looked at was vinegar. In this case household vinegar with a 5-percent acidity. The idea is that the vinegar kills the weed quickly without leaving a residual. The acid in the vinegar burns the top growth of the weed quickly as long as it is applied in dry weather. However it is nonselective and will kill everything it comes in contact with. The problem is though it doesn’t kill the roots and the top of the plant will quickly re-grow unless large amounts of it are used. Gillman found that the vinegar had to be full strength straight from the bottle which can get expensive.

•Beer is often used as a slug deterrent. The yeast in the beer is attractive to the slimy critters. Gillman found this worked reliably only if the container is sunk level with the ground and the beer poured to within an inch of the top. The slugs have to stretch to reach it and fall in. If the traps aren’t properly set the slugs will come in for the beer and then go after nearby plants.

•Lastly, I have a local myth I’d like to debunk. That is that pine needles from our native ponderosa pines acidify the soil. They don’t. Our soils generally have a pH of about 6.5 to 7.5 and pine needles added to the soil won’t change this enough to worry about.

Shredded pine needles are in fact a great mulch and bark replacement for shrub and garden beds. Run over them with a lawn mower and then spread them two to three inches deep around your plants. They pack down nicely but still drain water away quickly. If your home is in a fire prone area, don’t put them close to the house where they could catch a spark.