Q - I bought lady beetles for my vegetable garden this spring and turned them loose, but can't see any results. Are they worthwhile?

A - Lady beetles feed on several kinds of insects. Dealers collect them in large numbers to sell. Winter-collected beetles, when released in the spring, are likely to disperse quickly and widely, especially when the temperature reaches 65 F. and above. This means these beetles cannot be depended on to control insects in a given area.

Perhaps we should think more about protecting our local lady beetle populations. Spraying with an insecticide is likely to wipe them out. Plants infested with aphids and other insects can often be helped by using the garden hose to wash them off.

Q - I planted parsley in a planter; now the soil has suddenly turned gray, almost silvery. What could be wrong?

A - The gray or silvery crust probably signifies an accumulation of unused salts from fertilization or hard water. If the salt accumulation reaches toxic levels, plant injury occurs with marginal leaf burn and root destruction.

Monthly leaching should take excess salts through the drainage holes in the bottom of the container. At this point, the container should be completely immersed in fresh water, thoroughly saturating the soil. When the air bubbles stop rising in the container, remove it and drain. This procedure should be repeated twice, or until the water draining out of the container appears clear.

Q - The top two feet of my 15-foot-tall Chinese juniper turned down almost overnight. What could have caused it? It was a beautiful tree.

A - It probably was due to someone in the neighborhood spraying with a weed-killing chemical such as 2,4-D. With even a little bit of wind, the chemical can be blown and cause damage a block away.

Q - Our dogwood was in bloom nearly three weeks this spring. Down the street are two dogwoods that were in bloom nearly two months. Isn't that very unusual?

A - It probably was a combination of American dogwoods (Cornus florida ) and Japanese dogwoods (Cornus kousa ). The Japanese variety blooms soon after the flowers of the American dogwood fade.

Q - I bough petunias, zinnias and marigolds in packs; they were tall and spindly wiht no side branches, What can done to make such plants spread out and be attractive?

A - They were tall and spindly because they were too close together in the pack and were reaching upward to get light. Such plants in packs should be bought while they are small or not at all.

Pinching off an inch or two of the tops of the plants may cause side branches to develop on the lower part of the stems. Pinch them a second time when the upright-growing stems are four or five inches taller. This will result in more flowers but will delay the plants in coming into bloom.

Q - I try to grow blackberries and blueberries in my back yard, but the birds get most of the fruit. Is there any way to protect it?

A - Most birds feed close to a protective cover that offers them refuge when threatened. It might help to limit bird damage by removing these safe areas. When planting fruit-bearing trees and shrubs, do it away from such covers.

Q - I have two miniature roses that are growing outdoors in pots. What shall I do with them when winter comes?

A - In many areas they will survive the winter outdoors planted in the ground. In fact, they are more hardy than standard tea roses.

They are not likely to survive in pots outdoors in areas where temperatures go below zero. Planted in the ground, the soil provides some insulation against cold for the roots, whereas in pots the temperature will be approximately the same as the air temperature. The tops can survive lower temperatures than the roots can.

You can grow miniature roses indoors during the winter on a sunny windowsill or under fluorescent lights. If given good light and care, they should bloom continuously.

Q - Mistletoe is getting harder to find. Is there any way I can grow it?

A - Yes, if you can find some berries someplace, store them in a refrigerator. In early April, lift a small section of bark with a fingernail or knife and implant a couple seed in the twigs of last season's wood. Save some seeds and plant also in the current season's growth when it develops. Place the seeds on the underside of the twigs, where there will be less drying. Three years or more will be required for your mistletoe to produceberries. Mistletoe, like American holly, has both male and female plants, and the male will never produce berries. Mistletoe grows best on black gum, maple, elm and oak. Apparently, there are strains of mistletoe and some will grown only on certain trees. If you can, implant your seeds on the species of tree from which the seeds came: If they came from a maple, plant them on a maple.

Q - I've been afraid to use pine bark for a mulch near my house for fear of termites. Could they be a problem?

A - Very unlikely. Termites need a more solid wood base than bark provides, and bark does not provide them the tight enclosure they must have to survive.

Q - Is there a thing as warm-season lettuce?

A - Lettuce is a cool-season crop and can be grown in both spring and fall. Buttercrunch and Grand Rapids are two loose-leaf types that will tolerate some heat, but no varieties will grow well in midsummer.

Q - Can you give me a good recipe for soil for a window box in which annual flowers will be grown?

A - One part good garden soil can be mixed with equal amounts of peat moss and sand or vemiculite. Mix eight ounces of dolomitic limestone with each bushel of the final mixture. CAPTION: Illustration, no caption, By Zarko Karabatic