Q. I read once that it's best to leave garden soil undisturbed in the fall and winter, especially if the garden is on a slope, to prevent soil erosion. My garden is on a slope. Should I leave my vegetable and flower plants alone? Will they decompose in place by spring?
A. Plant debris should not be left in the garden. It may harbor overwintering pests and diseases, and many garden plants are semi-woody and will not decompose by spring. You could reduce erosion problems by cutting your garden plants at the soil line and leaving the root systems to hold the soil in place. The roots will eventually decompose, adding organic matter and improving soil structure.
Q. A very large spreading plant is taking over the banks of the little storm pond in our development. It starts out in the spring as upright shoots that resemble bamboo, then grows into a massive plant with long, light-colored flowers. We're concerned it will come into our back yards. What is it and what's the best plan of action?
A. Sounds like Japanese knotweed, a common invasive import that spreads by rhizomes and prefers moist, fertile locations. It is aggressive and should not be allowed to gain a foothold in your yard. Use a mattock and/or herbicide to keep it in check.
Q. There are small patches of very thin grass in my back yard, especially where the lawn baked this summer in full sun. Is it too late to plant grass this year? How much and what type should I plant?
A. You still have a few weeks to plant, but the sooner you reseed the better. Mow the thin areas to a height of 1 inch. Remove weeds by hand or spot treat them with a nonselective herbicide. Vigorously rake the area, removing grass clippings and thatch. Sow turf-type tall fescue seed at a rate of 3 to 4 pounds per 1,000 square feet of area. Rake the seeded area lightly, then cover it with loose straw. Keep the seedbed moist.
THIS WEEK'S CHECKLIST
1. Sow a late crop of lettuce, spinach, radishes and corn salad and cover with a floating row cover or cold frame.
2. Collect and discard rotted and mummified fruits -- grapes, peaches, tomatoes and the like -- that are on the ground or hanging from plants and trees.
3. Take advantage of the mild days and cool nights to plant trees and shrubs. Be sure to buy high-quality, healthy plants.
Garden tips are provided by the Home and Garden Information Center of the Maryland Cooperative Extension. 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.