Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: SUNDAY, August 13, 1995 TAG: 9508140029
SECTION: HOMES PAGE: C11 EDITION: METRO
SOURCE: JOHN ARBOGAST
DATELINE: LENGTH: Medium
The benefits of using cover crops include the addition of organic matter when it is incorporated in mid to late winter; an improvement in soil tilth and porosity; protection of the soil from erosion during winter, and the addition of nutrients.
Those cover crops known as legumes add nitrogen to the soil. This can be a great benefit, because nitrogen is known to leach readily from soils in this area. Treat the seeds of this type of cover crop with an "inoculant,'' which can be purchased at seed stores.
Ask at your favorite seed store for suggestions on garden cover crops as well as the amount of that seed that should be planted per 100 square feet. If you have late-summer (fall) crops growing where you want to use cover crops, sow the cover crop seed between rows about a month before you expect to harvest those vegetables.
Prepare the soil for cover cropping by tilling under ``clean'' plant remains or organic mulches from the summer. Scatter the measured amount of seed, hopefully shortly before a predicted rain, and rake it evenly into the soil.
Here are a few fall and winter cover crops that I consider outstanding:
Alfalfa - a legume that must be sown right away in Roanoke gardens to take advantage of weeks of warmth needed for establishment. It adds a large amount of nitrogen to the soil and grows deep roots that work to break up hard soil.
Hairy vetch - another legume, but it doesn't fix quite as much nitrogen as alfalfa. It is fairly hardy but still must be sown by mid-September around here. It must be tilled under before it seeds so it won't become a weed.
Winter rye - a nonlegume that is easy to work with - can be seeded in late October in Roanoke.
Q: I have a 35-foot hemlock in my front yard that has a heavy infestation of a small white scale insect. I have been told the tree will certainly be killed unless I have it sprayed at least once annually. Is there any alternative treatment? Because of the size of the tree and the fact that it will grow much larger, I hesitate to start on such an open-ended program. Also, what is the long- range prognosis for our native hemlocks if this scale insect is so deadly? Are they in danger of being wiped out? W.E.C., Stuart
A: As with any recommendation for spraying, a proper identification of the problem must be made first. I don't know of a scale insect that is bothering all our hemlocks, but there is a frequently occurring insect pest of hemlocks called the ``hemlock woolly adelgid'' that is very tiny but leaves small whitish puff balls along infested hemlock branches to protect its eggs.
If that is the pest you're referring to, control would be a good idea before the infestation gets out of hand and the hemlock is killed.
Pest control usually involves just one or two thorough sprays with a horticultural oil rather than sprays each year, unless the pest comes back in some future year.
Based on my observation, our native hemlocks definitely are ``at risk'' from the hemlock woolly adelgid.
Q: We have been gardening organically for the past three years and have been plagued by Mexican bean beetles. Is there anything that we can do to eliminate this pest organically? H.E.C., Covington
A: Frequently inspect your beans and hand pick those with yellow eggs, yellow, spiny-backed young stage beetles and adult beetles. Use the organic insecticide Rotenone, available at certain garden product outlets.
Send short questions about your lawn, garden, plants, or insects to Dear John, c/o The Roanoke Times, P. O. Box 2491, Roanoke, Va. 24010-2491. We need your mail, but this column can't reply to all letters. Those of wide appeal will be answered during the weeks that the subject is timely. Personal replies cannot be given. Please don't send stamps, stamped envelopes, samples, or pictures.
by CNB