Q. I like the idea of building my garden soil by planting a cover crop. But most of my veggies are still going strong. I don't want to pull them up to make room for plants I can't eat. What's an organic gardener to do?
A. Here are a few ways around your dilemma:
1)Remove the mulch from around your plants and between your rows and sow a cover crop on the bare soil. The young cover crops won't interfere with your vegetable harvest.
2) Pull up any spent vegetable plants and sow cover crop seed in their place. Good winter cover crops include hairy vetch, oats, winter rye and winter wheat. They should be sown by the second or third week in September, although winter wheat can germinate and grow in cool, early October weather. Edible cover crops, spinach, kale and turnip greens, can also be used. Always walk on newly sown seed to ensure good seed-soil contact.
Q. I have a few areas of lawn that are sparse and weedy. The soil seems to be pretty good, and I don't want to rent a tiller and re-do the whole thing. Is there an easier way to bring the grass back and get rid of the weeds?
A. The easier solution may be overseeding, but first you need to determine why there is a problem with these areas. Is it too shady, is there a drainage problem, are you mowing the grass too low, is the soil pH too low? Correct any underlying problems before you spend time and money trying to improve your lawn. To overseed: mow the target areas to a 1-inch height and rake out all the thatch and grass clippings. Eliminate the weeds by hand digging or with a non-selective herbicide. Sow a recommended turf-type tall fescue grass variety at the rate of 4-5 pounds per 1,000 square feet. Rake lightly and walk on the seeded area; cover lightly with straw and water daily.
Q. Is it OK to prune my white pine trees at this time? They have some dead branches and need to be thinned out.
A. It's fine to remove dead branches during the growing season. However, pruning live branches late in the summer will lead to heavy sap flow and signal the tree to produce new growth at the cut. This keeps your tree from getting ready for winter and can lead to winter injury. You can remove entire lower branches this fall to show off the trunk and lessen competition between trees. But do not shorten branches; it ruins the tree's shape and opens the tree to insect and disease problems. Thinning can be accomplished in the spring by removing the "candles" that contain the new bundles of needles. If your trees were planted too closely, you may need to consider having some removed to make room for the others.
THIS WEEK'S CHECKLIST
1. Take advantage of the mild days and cool nights to plant trees and shrubs. Be sure to buy high-quality, healthy plants.
2. Take a soil sample from areas of your landscape that have not been tested in the past three years. Be prepared to raise the soil pH with lime or lower the soil pH with sulfur according to test results.
3. Prevent insects from moving into your home by tightening up screens, and caulking and weather-stripping around door thresholds and vents.
Backyard Q&A; is by Jon Traunfeld, regional specialist for the Home and Garden Information Center, Maryland Cooperative Extension Services of the University of Maryland. For additional information on these questions, or if you have questions of your own, call the center's hot line at 800-342-2507, or visit its Web site at www.agnr.umd. edu / users / hgic.