Vegetable gardeners often have more green beans, tomatoes, beets, broccoli and leafy greens than they can use. Canning them can provide safe, inexpensive quality food if tested, approved methods are used.

Properly canned and stored foods should be safe to eat for more than two years, but for top quality it's best to can only enough for use in one year.

Or you can freeze your vegetables. If you're not sure how well something will freeze, test it before freezing large quantities; simply freeze two or three packages and sample the food a couple of weeks later.

Home canners should not take shortcuts, according to specialists. Organisms that cause food spoilage -- molds, yeasts and bacteria -- are always in the air, water and soil. Raw fruits and vegetables contain enzymes that may cause undesirable changes in flavor, color and texture.

When fruits and vegetables are canned, they must be heated hot enough and long enough to destroy the spoilage organisms and stop the action of enzymes.

Small berry and stone fruits, asparagus, green beans, beets, broccoli, corn and leafy greens, among others, should be preserved the day of harvest for highest quality. Apples, peaches, pears, plums and tomatoes, if harvested at firm maturity, should be ripened a few days before canning them. Other fruits and vegetables may be stored for a week or longer before canning without significantly lowering their quality.

Bacteria are the most serious threat in canning because they are more difficult to kill by heat than either molds of yeasts.

Since few bacteria thrive in acids, their destruction is less difficult in fruits than in vegetables, with the exception of tomatoes.

Low-acid vegetables include asparagus, snap or shelled beans, carrots, corn, potatoes, pumpkins, squash and sweet potatoes.

High-acid fruits and vegetables include apples, apricots, berries, cherries, grapefruit, peaches, pineapple, rhubarb and tomatoes.

Yeasts, mold and non-spore-forming bacteria are readily controlled by processing at 212 degrees F.

Most canning equipment and supplies may be purchased at hardware stores, housewares departments, and from mail order companies.

Storage temperatures 50 degrees to 70 degrees F. are satisfactory. Q: How long does it take for tomatoes to ripen after they form on the plant? Is there a guide for them and other vegetables? A: Tomatoes mature in 30 to 45 days, depending on variety and time of planting snap beans usually in seven to ten days after flowing; cucumbers for pickles in four or five days; summer squash five to six days; winter squash such as Hubbard in 11 to 12 weeks; sweet corn 18 to 24 days after silk appears; and sweet peppers 40 to 50 days. Q: The brick pavement of our patio is covered with moss. How can we get rid of it? A: Burn it off with ammonium sulfate, a high-nitrogen fertilizer. Wet the moss and spread the fertilizer over it. Later on use a wire brush to remove the dead roots. Q: I've been letting the clippings stay on the lawn instead of raking them up. Is it all right to do so? A: Grass clippings provide substantial quantities of nitrogen fertilizer as they decay. Tests have shown that when the clippings are removed, an additional two pounds of nitrogen per 1,000 square feet may be required each year. Q: My azaleas are getting too tall; can I cut them back without hurting them too much? A: They can be pruned. The best time is before growth starts in the spring, or soon after they finish blooming. Pruning older wood may result in loss of flowers the following spring, but it can also result in more attractive plants and better flowers in succeeding years. Q: A big green worm is feeding on the leaves of my tomato plants. How do I get rid of it? A: It's the tomato hornworm; pick it off, it can't sting or bite. Q: The temperature where I live sometimes goes down to zero during the winter. Is there any way I can grow figs other than in a greenhouse? A: Plant the fig in a tub or bushel basket and winter it over in the cellar or basement of your house, or in the corner of an attached garage. If you use an unattached, unheated garage or shed, place a burlap bag over the fig.Figs have wintered successfully this way in the New York City area when temperatures dropped to 15 degrees below zero.You can move it outdoors about the same time you plant your tomatoes. It will need watering regularly and a once-monthly fertilizing during the summer months. If the soil gets dusty dry during the winter give it light sprinkling. Q: Our tomatoes and beans are getting ripe and we are going away for two weeks on vacation. Any suggestions? A: You can make a big hit with friends or neighbors by inviting them to help themselves. Before leaving, be sure to pull all the weeds in sight. Q: My hydrangeas are getting too tall. When is the best time to prune them? They are the ones that have pink flowers. A: The time to prune is immediately after the plant finishes blooming. Stems can be cut back to the second or third set of leaves, or nodes. Be careful not to injure the buds in the axils of the leaves where the cut is made. These will start into growth that will produce next year's flowers. q: I planted radishes this spring and all I got was leaves. How come? a: Sowing the seed too thick and not thining when they come up is the usual cause. The plants need to be spaced at least an inch apart after they come up. Q: Should Oriental poppies be divided? I've had mine six years and the clumps are quite large. A: Don't disturb them unless it's necessary to move them. Q: What causes leaves on my birch tree to become wrinkled and discolored? A: Usually it's due to aphids (plant lice) feeding on the leaf tissue. Malathion can be used as a spray to get rid of them; however, effective spraying of a big tree is usually not a do-it-yourself project, and if you don't spray, predators may move in and reduce the aphid population before much damage is done. Q: We feed our daffodils well after blooming each year and allow the leaves to remain untouched until they have died down completely, but all we get is healthy leaves and no flowersl What could be wrong? A: You may have been over-fertilizing them and they are now badly crowded. If that's the case, dig them up, separate and replant the largest bulbs. The small bulbs can be planted elsewhere to grow to flowering size. q: Two years ago. I planted a Japanese maple, and now it's no bigger than it was when I planted it. How can I make it grow? a: When one of these trees is transplanted, it may take two or three years to recover and start growing again. If you didn't plant it too deep, and if you keep it watered during dry weather, it should start to grow for you soon. Some may take 10 years to reach a height of six to eight feet.