There's a lot to be said for living in a tropical rain forest, as we have been lately. It makes your garden grow like a jungle.

It seems hard to believe, but the National Weather Service says that so far, August's rainfall has been pretty close to average. The long- range forecast, however, predicts a hotter and wetter August than usual.

Rain makes a body feel fine, especially if the body belongs to a gardener.

For a truly spectacular fall vegetable crop, you want a season that duplicates, as nearly as possible, spring. Add some already warmed soil, a lot of hot, muggy air, and there's just no stopping those seedlings.

August-planted seeds will sprout faster than spring seeds because they don't have to wait for the soil to warm up. Annual vegetable seedlings love rain and heat, so they, too, will grow more rapidly than their springtime brethren. Gardeners who have planted fall gardens before know how ideal Washington weather is for fall gardening.

Because plants grow so quickly at this time of the year, weeding and mulching are even more important now than in the spring. With the hay season under way, there's always some unlucky farmer who's had some of his crop rained on. County weeklies are full of ads for mulch hay. A lot of people claim that putting down newly mown hay causes weed problems because of weed seeds in the hay, but I've found that the advantages of having that good, wet hay on the ground far outweigh any minor weed problems.

Good hay does wonders for the soil, adding nutrients that feed important micro-organisms through the winter. Successful weeds will sprout on top of the layer of hay and will be far easier to pull than weeds that have sent their roots deep into the soil. Heat from composting hay and, later, cold from winter frosts will combine to kill off weed seeds, so that by spring, whatever weed problems mulch hay may have introduced into the garden will be pretty much resolved. BULBOUS: Order bulbs this weekend. Most nurseries that feature bulbs for fall planting have mailed out their catalogues, so there should be plenty of choice. Garden and hardware centers have many bulbs on dis play. While it's cheaper to buy locally, (you don't have to pay shipping costs), most retailers carry a smaller selection than the mail-order houses since they stock only what they know will sell well. Fall-planted bulbs include all those gorgeous spring bloomers: daffodils, narcissus, crocuses, tulips and hyacinths. Many gardeners use flowering bulbs as border plants, and they lend themselves well to this; but I like to see them naturalized, an increasingly popular way of growing spring- flowering bulbs. Naturalizing, in effect, means letting the bulbs multiply and thus spread, and more bulbs are being developed for just this purpose. A most attractive way of planting them is to scatter the bulbs about on the lawn, under tall trees or edging the lawn, and then punch a hole in the ground wherever a bulb has fallen. Insert the bulb, cover it with some decent soil, and forget about it. Over the years, the bulbs will multiply underground; eventually you will have great clumps of flowers where you originally planted only one bulb. After several years, you may want to dig the bulbs, separate them, and start the process all over. Bulbs are marvelous because they are so very easy to plant, and they take care of themselves.

BLOSSOM-END BUMMER: As tomatoes ripen, there's always somebody who'll ask why some tomatoes have a dark, rotted look on what should be the smooth, rounded tips. What such a person is looking at is blossom-end rot, which can also affect summer squash. It's caused by lack of calcium in the soil. I have said it before, and I'll say it again: When you put your tomato seedlings in, add a handful of limestone to the soil. You can mix it in or just let it lie on top. Later, when the tomatoes have achieved good growth but before a lot of fruit has set, say in late June or early July, add more limestone. At this point, there's not a whole lot you can do about blossom-end rot. There are some sprays available; supposedly, the needed calcium is absorbed through the plant's leaves. I can't honestly say whether these work or not since I haven't had to use any; gardeners who have, report mixed results. Your best bet, if you have a problem, is to spread some hydrated lime now (hydrated lime is absorbed more rapidly than ordinary ground limestone), and make sure you put down limestone next spring. I might add that it's unusual not to get some fruit that displays blossom- end rot, even when the soil is sweetened to the 7.0 pH that tomatoes prefer.

A READER WRITES: My pepper plants are large and bushy, but there are no peppers on them. Can you tell me why? A. You're probably using too much fertilizer. There are a number of hot- weather annuals, peppers especially, that produce much better with less feeding. The plant will look good but fruit won't set, probably because the plant doesn't feel the need to make offspring since it's doing just fine. If you are feeding it, stop. If the soil itself is quite rich, you may want to consider transplanting into a pot. Use a pot large enough to contain the root system comfortably, but one that limits the amount of soil so the nutrients don't get to it as quickly as they now do. You could put the pot right into the ground from which you took the pepper plant. This helps keep the potted soil from drying out too rapidly. If you don't think over-fertilizing is causing the problem, many gardeners say that laying aluminum foil around the plant often stimulates the production of peppers. It makes sense, since peppers thrive in hot, glaring sun, and the aluminum foil will reflect the sun and amplify it around the plant.