Right about now is the best time to seed a new lawn or ejuvenate an old one. The new grass will have a longer time in which to become established before having to cope with hot, dry summer weather.

The first decision is whether to do the whole lawn over or just patch it up. If there is grass fairly well established over 50 percent of the lawn, it's probably better to repair than to start over.

Try to figure out why there are bare spots. Seeding or sodding bare spots alone will not be a permanent cure: The new plants will die for the same reason the old ones did.

A female dog can cause bare spots. In such cases, the old soil should be removed t a depth of three or four inches and replaced with good soil.

Too heavy an application of salt for deicing the sidewalk during the winter can kill grass. Hard-packed soil caused by heavy foot traffic, soil too acid or hot summer weather without rainfall can cause bare spots.

An easy way to fill them is by sodding. Chunks of sod can be taken from inconspicuous places and used to fill the bare ones. Or you can buy a few rolls of sod and cut it into pieces of the required size.

To seed the bare spots, use the same mixture that is prevalent in the rest of the lawn. If you don't know what you already have, make a guess.

Don't waste seeds by just throwing them on and hoping Mother Nature will do the rest. First get rid of the weeds and use an iron rake to scratch up the soil.

The seeds need light to germinate, and unless they are in good contact with the soil they may dry out rapidly and perish.

Moisture is a critical factor in grass-seed germination and survival. If the embryo dries out at any time after it starts to grow it dies. That's why it's necessary to keep the seed bed moist by sprinkling one or two times a day.

After the grass is up and growing, water instead of sprinkling, if rainfall is inadequate.

Lime and fertilizer should be worked into the soil to a depth of two to three inches. Fifty pounds of ground limestone and 15 pounds of 5-10-5 fertilizer should be applied per 1,000 square feet of lawn.

A good all-round lawn mixture should include 50 percent Kentucky bluegrass (use two or three kinds such as Baron, Bonniblue, Fylking, Merion), 25 percent red fescue and 25 percent Pennlawn or Manhattan ryegrass. Seed at the rate of three pounds per 1,000 square feet.

If your houseplants were outdoors for the summer, now is also the time to bring them back inside. It will give them time to adjust to the changed environment before windows are closed and the heat is turned on.

The big problem may be light. If they have been getting high light intensity (direct or filtered sunlight) they need to be adjusted gradually to low or medium light indoors.

The plant's leaves produce its food by the process of photosynthesis. A plant that's adjusted to low or medium light intensity usually will have large, thin, dark-green leaves.

Such leaves are incapable of food production and are intolerant of high light intensity. Yellowing and leaf drop soon occurs. Then, slowly, the plants revive over the summer.

When the plant is returned to the low or medium light intensity indoors, it quickly drops its new small, thick light-green sun leaves. To survive it must acquire new leaves that are shade-tolerant.

That can be accomplished by bringing it indoors daily for three or four hours for about 10 days, then daily for six hours for another 10 days, and then leaving it indoors.

The plant will need to be watered more often while it's being adjusted to the changed environment than when it's kept indoors full time.

Instead of the gradual adjustment, the plant can be put under fluorescent light, which does an excellent job of growing high-quality plants.

A plant adjusted to low or medium light intensity should be put under fluorescent light gradually to become accustomed to the changed environment.

Before bringing the plants indoors, check them carefully for insect pests and disease. Aphids (plant lice), mealy bugs and spider mites are the ones most likely to infest them.

For aphids use one teaspoon of mild dishwashing detergent in a gallon of water to spray the plant. Such a mixture is mildly toxic to aphids, according to John A. Davidson, University of Maryland entomologist.

For mites an mealybugs, spray with kelthane or try to wash them off with the garden hose (they are mostly on the underside of the leaves). It may be necessary to repeat several times to get the ones that probably will hatch out from eggs on the foliage. Q: This year we have a lot of slugs. Two of our neighbors have them also. How can we get rid of them? A: Mensurol has been approved by EPA for slug control around the home and in gardens. Follow directions on the label. Also get rid of the places where slugs hide during the day. Tin pans of stale beer have been used -- it attracts them and they get into the beer and drown. Q: How deep should grass seed be planted in a new lawn? A: The standard recommendation is to rake the grass seed into the top quarter-inch of soil. There the seed will get enough light to germinate and have good contact with soil and mositure. Q: Three years ago we planted four crabapple and four flowering cherry trees in the yard of our new home. So far, not one of them has bloomed. Is there something we can do to speed them up? A: There are several reasons for poor or no flowering of trees that should bloom insufficient light; heavy pruning; plant immaturity; winter and frost injury; and excessive fertilization. And sometimes no flowering is a natural phenomenon. If the environment is all right, just be patient -- they'll bloom in time. Q: Our tomatoes don't taste as good as they used to. Is there anything we can do about it? A: Tomatoes in the garden should be harvested when they are fully vine-ripened and not before. The fruit will pass through various stages of coloration before becoming red-ripe. The quality is usually highest when color is a dark red (red varieties). They cannot be stored for very long. Q: There is a silver maple tree in my yard. I plan to cut it down and use it for firewood this winter. Are there precautions I should take? A: A newly cut tree may be more than half water. Trying to burn fresh-cut or green wood can give you some problems. Q: My azaleas are mulched with about three inches of peat. Is this too little or too much? A: Specialists recommed a mulch of about two inches, which is sufficient to prevent deep freezing of the soil. Overmulching can be damaging to shallow-rooted plants such as azaleas, boxwoods and rhodoendrons, because plant roots can grow into the mulch and be killed during a cold, windy winter. Peat is not the best mulching material: It's easily blown away, weeds can push through it, and when it dies it forms a hard crust that sheds water. Q: When do you apply lime to a blue hydrangea to make it bloom pink? A: In late summer. Apply one tablespoon of hydrated lime per plant, work the lime into the soil around the roots. Prune them immediately after they bloom; flower buds form in the fall and pruning later than that will remove them. Q: We want to plant a lot of hyacinths this fall. When is the best time to do it? How far apart should they be planted? A: Plant hyacinths anytime during October and November, six inches deep, five to six bulbs per square foot. They will continue to bloom each year. The first-year blooms are always superior, after which the flowers get progressively smaller. It's important to allow the foliage to turn brown and die in the spring before cutting it off.