Q. We have a new home, no trees and only a few shrubs, and we need some kind of windbreak from winter winds. What is best? A. Tests of wind currents have shown that wind flows nearly the same way as wter. A solid fence acts as a dam and spills the wind over the top. A lath fence with spaced laths diffuses and breaks the force of the wind. A hedge does the same thing, and the denser the foilage, the better the protection. Curved plantings of evergreen trees and shrubs in the form of a high hedge can guide winter winds around and away from the home. Q. I collect pine cones for decorations and they last only a short time. What is wrong? A. It is best to collect mature cones while they are in the green or light brown stage and allow them to ripen or dry out in full sunshine. They will also open fully if placed in a warm oven for several minutes. They can then be preserved by spray painting them with clear shellac, lacquer or clear varnish. Q. I've been told to use rubbing alcohol to kill mealybugs on my house plants. Is it also good for other kinds of insects? A. Rubbing alcohol is an effective wetting agent, penetrating an insects's waxy protective coating and carrying the insecticide into the insect's body. Measly bugs are especially vulnerable to it. With other insects, rubbing alcohol can be added to insecticide. But be careful: alcohol may carry poisons into the human body as well. Q. Last spring I put fresh horse manure on my vegetable garden; now it is filled with mushrooms. How can I get rid of them? Are they harmful to my vegetables? A. Fungi that get their food from organic matter are responsible for the mushrooms. They do no harm to the vegetables. When the food supply is exhausted, they will stop appearing. Pick them as they appear and put them into the garbabe can. Don't eat them: many kinds are dangerous. Q. What is the life of Malathion and Sevin? How long are they effective against insects? A. They are effective for about two days after they have been sprayed on surfaces exposed to sunlight and for about four days on shady surfaces. In unopened containers the shelf life is two or more years, in opened containers about six months. Q. Can cuttings from petunias be rooted? We have some very unusual hybrids and I'd like very much to try my luck rooting some cuttings to use as house plants this winter. A. Petunias root easily. Take cuttings four to six inches long and root in coarse sand or a mixture of one-half coarse sand and one-half finely ground peat.