Ask the gardeners

I received a beautiful fuchsia plant in early June in a hanging basket. It was beautiful at first, but after a while the buds started dropping and the leaves turned yellow and began to drop as well. I've had it hanging on my patio, where it gets plenty of sun, and I water it every few days until the water runs out of the pot. What's wrong?

Fuchsias prefer cool weather and semi-shade or filtered sunlight.

Outdoors in the sun, the plants dry out quickly. Any hanging basket needs to be watered daily if the weather is dry. When the plant is hung in the sun, its soil ball dries out quickly and shrinks away from the sides of the pot.

Then, when water is applied, it merely runs down the sides of the soil ball, letting it dry out more and more.

Simply, the buds and leaves shed because they don't get enough water.

We suggest you trim the plant back to within 6 inches of the pot and let it come on again. Root cuttings for friends. Moisten the soil ball thoroughly after cutting it back by immersing the pot in a pail of water. Then water it each time before it gets to be bone dry.

We have a Bartlett pear tree which is about six years old. Last year the leaves turned partly black, although most of the fruit was good. What causes this black ''dust''?

Pears are attacked by an insect known as ''pear psylla'' (sill-uh), a sap-sucking pest that is related to plant lice or aphids.

The immature insects secrete a sticky substance (called honeydew) which becomes blackened by fungus spores that land on it. The presence of this blackish material (called ''sooty blotch'') is the first indication of the pest.

Chemical gardeners spray with Sevin or nicotine sulfate when the fruit is the size of a large marble, or with a dormant spray (ask for it by that name at a garden store) on the ground in late fall to kill the hibernating insects.

Organic gardeners can use 1 tablespoon of liquid household detergent plus 1 pint of rubbing alcohol in a gallon of water or one-half cup of shavings of Fels-Naptha soap dissolved in a gallon of water.

Fruit with sooty blotch or blackish mold is perfectly safe to eat. Rinse off after washing with a little detergent water.

Our problem is bats which roost in the shed and make a mess. I wouldn't mind their roosting there if it weren't for the droppings. How can I get rid of the creatures?

If your shed is enclosed, try to close off the bats' entrances. If that's impossible, spray the roosting area with tacky materials, such as Roost-No-More or Tacky Trap.

Write to Animal Repellents, Griffin, Ga. 30233, for literature.

Incidentally, the droppings are called guano, which makes an excellent fertilizer. It was highly sought after before supplies (primarily in South America) were nearly depleted. Peruvian natives used it for centuries.

I noted your advice to use cardboard rollers from toilet paper, paper towels, and wax paper to put around plant stems to thwart cutworms. Your readers might like to know that I use 61/2-ounce cans, about the size that orange juice comes in, with the tops and bottoms removed.

That's a good idea to control the surface cutworm.

The cans should be pushed into the soil an inch or more to foil the worm, which is usually lurking somewhere just beneath the soil surface. Because of their in-soil habitat, don't use larger cans; they could be inside the rims.

There are four types of cutworms. Some bother crops all over the world. There are the surface cutworms - the ones controlled by paper collars, wax paper, tinfoil, and tin cans. In addition, there are climbing cutworms, subterranean cutworms, and army cutworms.

Last spring my husband cut up a load of logs for firewood. Then he put the sawdust on our vegetable garden space and mixed it all in. None of our vegetables have grown well. What should be added to the soil to bring back its fertility?

Sawdust is fine to add to the soil if a balanced fertilizer is added to it as well. About one cup of dry fertilizer or a quart of liquid fertilizer solution to a bushel is usually sufficient.

What happens is that the nitrogen-producing bacteria are so busy breaking down the sawdust that they aren't furnishing any to the plants.

Fertilizer added now and again in early spring will do a fine job of ''pepping up'' your soil for next year's crops.

Don't forget that compost and rotted manure are great soil amendments, as well, and they don't have the same effect as fresh sawdust.