Gardening Articles: Landscaping :: Trees, Shrubs, & Vines
Gardening Fact...or Fallacy?
by Robert Kourik
Though plants, soils and weather conditions are always evolving, it seems as if some gardening practices become embedded like fossils. I once encountered, for example, a person whose family had heard that whacking the trunk of a tree with a newspaper every night would increase its diameter, and so he whacked his trees regularly, too. With newspaper, the practice may be harmless, but substitute a board or a stick and it wouldn't be hard to seriously damage vital tissue just under the bark.
Tree whacking is easy to pooh-pooh, but what about tree staking? Recent studies at the University of California at Davis have shown that most people stake their young trees needlessly and for too long. The cords and wires (even cushioned with a piece of rubber hose) can damage the cambial layer and retard growth of the trunk. It's an entrenched practice that injures plants rather than helping them get stronger. Although time-honored gardening techniques and folk wisdom can be valuable resources, gardeners who don't constantly check their assumptions run the risk of working hard to no good end, or worse, actually harming their plants.
Here's a checklist of six widely held gardening assumptions for you to measure against your own practices. The trick to a lifetime of effective gardening is to stay flexible and be willing to change the things you do, based on your own observations and the guidance of modern research. Remember, if you don't keep growing, your plants may be suffering too.
. Watering on a sunny day can burn plant leaves.
A good gardener is a good observer. Have you ever seen a forest (or a garden) littered with the carnage of leaves fried by the sun shining through rain droplets? Thunderstorms arise every summer with amazing speed and the sun often comes out afterward. Plants are well adapted to deal with this. You'll never find burn damage on leaves after watering plants with a sprinkler of any kind. Any holes "burned" in leaves are due instead to fungal or bacterial diseases and have nothing to do with sunlight shining on droplets.
A good reason not to water at midday, however, is that the moisture you supply will be lost much more quickly to heat or wind then. Water promptly whenever you see that plants need it, but the ideal time is in the morning when the water has a chance to drip from the foliage and soak through mulches.
2. Remove lawn clippings or they'll make thatch.
According to the Lawn Institute, thatch is produced more by the misuse of strong fertilizers and pesticides than by clippings alone. Thatch is a layer of dried grass clippings that builds up on the soil surface. As long as this layer is less than 1/2 inch, it's harmless and in fact has some of the same benefits as a mulch. A healthy soil biota can easily decompose the normal amount of clippings to keep the thatch layer from building up. But earthworms, which perform much of this task, are especially vulnerable to popular lawn chemicals.
For a healthy lawn, mow frequently. Short clippings are tender and rot quickly. Set the mower blade high -- thicker lawns shade out weeds. Adjust the pH to 6.5 to 7.5, the range favored by most grass species. Fertilize only if the lawn really needs it; if you are leaving the clippings, they will return fertility to the lawn.