Pruning your apple trees; living mulch pays dividend

We just bought an old homestead on which there are half a dozen old apple trees that are overgrown. Former owners identified them as Northern Spy and Wealthy. Could these trees be pruned back to some kind of manageable shape so they will bear? If so, how and when should it be done? More and more people are getting interested in old-fashioned apple varieties. Many nurseries now offer them.

If your trees are basically sound, without dead limbs, you can gradually get them into shape over a period of two or three years.

Winter, while they're dormant, is a good time to prune. Remove any dead branches and those that crisscross one another. Skinny, weak limbs and those that prevent light from getting to the center of the tree, should be removed. Take care not to overprune the first year.

Since space does not permit a detailed description of the pruning process, those interested can get one of our Fruit Tree Pruning Guides by sending a self-addressed, stamped envelope to this column, The Christian Science Monitor, One Norway Street, Boston, Mass., 02115.

I have a bed of pachysandra around a crab apple. Will this rob the tree of nutrients? Not as long as it is shallow rooted, which pachysandra is. Many people use such a living mulch around a tree. It keeps the lawn mower away from the trunk.

What are your comments on a gold-colored beet? We have small space, so don't want to chance it if it does not have a real beet flavor. Will it measure up to red varieties? The one we are familiar with is Burpee's Golden Beet - truly delicious and even sweeter than most other beets. The beet greens are as good as any we've tasted.

Although we prefer to eat them when small to medium in size, last year's beets grew fast and, in fact, we found the large ones just as tender, just as sweet.

The seed-germination rate of Golden Beets is a little lower than that of red beets, so you'll want to sow them just a little thicker.

I have two cans full of leaves, and would like to change these to compost by spring, if possible. How can I do it? As long as you have the leaves, why not combine them with your table scraps and convert it all to compost?

Get a third can and put 3 or 4 inches of leaves in the bottom, plus a sprinkling of soil. Add a few leaves after adding each day's table scraps. You can also add some shredded paper. All kinds of vegetable and fruit peelings can be used, plus coffee grounds, tea leaves, and the like.

If you want to add some red worms, they will make it break down faster, but then you must not add onion skins, which repel earthworms of all kinds. For sources of earthworms or red worms, look in such publications as ''Organic Gardening and Farming,'' a product of Rodale Press, Emmaus, Pa. 18049.

If you use worms, you must keep the cans above freezing. It also slows the composting to have the cans where it is below freezing.