ASK THE GARDENERS

March 5, 1985

Q Last fall I was given a gloxinia that produced a dozen or more beautiful blooms before it stopped flowering. I moved it to a table in the bedroom and in January I discovered a couple of buds. However, the stems are long and spindly. Should I remove some bottom leaves and set the plant deeper in the pot? Setting the plant deeper would cause the stem to rot. The plant is reaching for light and suffering from lack of a rest period. Although miniatures will bloom continuously with proper care, large-leaved ones do best if dried out after bloom and allowed to rest for two to three months.

Tubers can be stored in a cool room or basement (in the pot). Water only enough to keep tubers from shriveling. When new growth starts, repot it in soil suitable for African violets, increase water gradually, and feed once a month while in active growth. As soon as repotted, set pot in bright light. Plant can get sun in winter and early spring, but sunlight should be filtered in late spring and summer. Q You may have answered this question before, but I have not seen it. I love my cats, but how can I keep them out of my houseplants? They chew on some and dig in the soil of others. . . . I suspect they think it's kitty litter.

Some of these suggestions from readers have worked for us: Orange peels scattered on soil stops digging, as will toothpicks stuck close together in the soil. Hardware cloth can be fitted around the plant, inside the pot. Above all, make sure litter box is kept clean.

Cats seem to need greenery in their diets in winter, so grow some grass, oats, or wheat from seeds. Also, you might keep a plant such as chlorophytum (spider plant) or dracaena (corn plant) just for pets to chew on.

A precaution: If you have just bought a plant from a florist or garden center, keep it out of reach of pets or small children for 30 days. Many growers use Temik, a very toxic systemic pesticide. Supposedly plants are safe to sell within 30 days, but we advise taking precautions for 30 days more. Not enough research is being done on Temik (and other toxic pesticides).

Another precaution: Philodendrons and dieffenbachia (and a few other houseplants) have a natural toxic substance in leaves and stems, so don't let cats nibble on these. Stick with chlorophytum and dracaena -- favorites of cats. Q Last year my pole beans were ruined by spider mites, but I didn't recognize the problem until webs appeared on the plants. A neighbor suggested insecticidal soap, but by that time they were too far gone. We used the solution to drench the vines, then cut them off and put them in a plastic bag for disposal. Is there some way to recognize the presence of mites in their early stages?

Since mites are almost invisible to the naked eye, experienced gardeners look for mottling and yellowing of foliage. You can use a magnifying glass on undersides of leaves, or you can hold a white piece of paper under leaves and tap leaves sharply with a pencil. If tiny crawling specks are noted on the paper, then apply a pesticide.

Fortunately, there are several good natural ones. Plain water will cause mites to bloat (a reason they multiply during dry weather), but pesticidal soap made into a spray is a more thorough control. The all-purpose formula of one tablespoon each of liquid household detergent and hot pepper sauce in a gallon of water is good. We add a cup of rubbing alcohol to this. If you don't mind a white residue, you can use 1/2 cup buttermilk and 4 cups wheat flour in 5 gallons of water. Spray once a week for three weeks, being sure to cover both tops and bottoms of leaves to get newly hatched mites. Q We have a large citrus plant in our home, which former owners left for us. It is very healthy, flowers beautifully, and produces many tangerine-size fruit. However, the fruit is sour and bitter. Is there some way I can make it produce sweet fruit?

No. The plant was probably started from seed and such plants usually produce ``common'' or wild fruit, although foliage is handsome and flowers fragrant.

The only way to grow edible citrus fruit is to buy ``budded'' plants from a nursery or garden store. These are grown from a rootstock to which has been grafted a bud of a known variety. Q I know winter is a good time to prune fruit trees, but is it a good time to prune spring-flowering shrubs, such as forsythia, flowering quince, and bridal wreath spirea?

If your shrubs are really overgrown and winter is the only time you can get at the pruning job, go ahead and prune out the old thick canes and cut back some of the newer growth. If the shrubs are full of dead growth, you may want to cut them back to a few inches above the ground and let the new growth come up.

Ideally, spring-flowering shrubs should be pruned right after they bloom to prevent new flower buds from being pruned off.