One of the big problems for gardeners, particularly new ones, is sowing seeds that fail to come up. Several attempts have been made to make seed-sowing easier, such as seed tapes, with seeds spaced in a paper strip, and seed pellets, seeds coated to make them easier to handle. But none of these efforts took care of the basic problem of germination.

Now a new seed-sowing system, developed by National Vegetable Research Institute in England, not only permits gardeners to test the viability of seeds before planting them, but also eliminates the risk of poor germination outdoors.

Tested successfully in this country, the system is available as a kit from Thompson & Morgan, Box 100, Farmingdale, New Jersey 07727, which will send a free-catalogue on request.

The seeds are germinated indoors in trays to avoid outdoor hazards. As soon as the seedlings have emerged through their seed coats, they are stirred into a clear organic gel, which is then poured into a plastic applicator, resembling a large tube of toothpaste. When you squeeze the applicator, the seedlings flow out into the soil along a prepared furrow, and can be covered with soil. The fluid automatically disappears, leaving the seedlings to continue growing. They can tolerate much cooler temperatures, so even if a cold spell follows fluid sowing outdoors, they will not normally suffer.

In cold springs this new method often produces plants two to three weeks ahead of normally sown seed, says David Gray, of the vegetable research institute, in a report published by the Journal of the Royal Horticultural Society.

"With all vegetables so far tested," Gray says, fluid sowing of pre-germinated seeds gives higher and more predictable emergence than dry seeds.

"With crops such as salad onions, parsnips, carrots and parsley, which normally germinate slowly from early-spring sowing, fluid sowing usually provides much earlier emergence.

"Other good examples of planting pre-germinated seeds are lettuce and celery. Lettuce will not germinate at high soil temperatures and succession sowings during summer often fail to germinate. By pre-germinating the seeds indoors under cool conditions, they can be fluid-sown into the garden for rapid growth and development. Celery seeds need light to germinate, which can be provided by this method." Q: I want to grow some petunias, marigolds and zinnias in pots on my patio this coming summer and use some of the flowers for arrangements indoors. It is practical? A: These plants will grow very well in pots if given sunlight and good care, and there should be plenty of flowers to cut and use indoors. I can't overemphasize the importance of keeping the plants watered and giving them a little fertilizer occasionally. Q: We have an old scrub apple tree near some good bearing trees. Will its pollen alter the quality of their fruit? A: The fruit produced as the result of pollination is characteristic of the female parent regardless of the variety that furnishes the pollen.

It may very well be that the scrub tree is serving a useful purpose by providing pollen for the trees that are producing good fruit. Q: We have a zoysia lawn. For years it has been beautiful but last summer for some reason white clover took over and is choking out the zoysia. How can I get rid of the clover? A: It would be very difficult for clover to get started in a well-established zoysia lawn, so something must have happened to the zoysia to weaken it. Your problem is to find out what happen and correct it. Research has shown that mowing zoysia at about one inch is best for weed suppression. Q: I brought some small geraniums to my windowsill in early September. Instead of growing normally, they have become much too tall. What would cause that?sn A: Inadequate light is the usual cause; geraniums need a lot of sunlight. Too much nitrogen fertilizer also could be the reason. Q: I brought some wax begonias in for the winter, and half the time they are badly wilted. What would be the reason? A: Most likely they're being watered improperly. When the soil feels dry to your touch, water them thoroughly. Q: My husband brought home a bushel of apples. How can I keep them solid and tasty? A: Apples kept at 31 degrees F. and 85 percent humidity will have good taste and texture for a long time. Try keeping them in the garage, on the porch or some other storage area outside the home -- even the trunk of your car. Q: My iris needs to be moved to a new location. When is the best time? A: It can be done successfully almost any time of year but the best time is during June and July soon after they've flowered. Q: I have been growing vegetables in the same place for 15 years, and it seems to me that quality and quantity are off despite plenty of 5-10-5 fertilizer. A: The soil probably needs organic matter. Compost is one of the best materials to use; well-rotted barnyard manure and peat moss are also good. Q: My 20-year old red maple had to be cut down; the surface roots had become a serious problem and it was too close to the house. What can I plant that's good for a small back yard, does not have a root problem, gives some shade and is not very large? A: One of the crabapples may be just the tree for you. They range in height up to 20 or 30 feet, have lovely blossoms in the spring, and the roots should not become a problem. Q: I tried to grow marigolds and zinnias in a shady place in our front yard last summer. They didn't do anything. What can I grow there that is colorful? A: There are several degrees of shade: low shade, high shade, light shade, deep shade, dry shade, moist shade, morning shade, afternoon shade. Coleus, impatiens and wax begonias are the most successful flowering annuals for a wide range of shade conditions. Q: We haven't had crabgrass in our lawn for several years; we have been using a crabgrass preventer. Is it necessary or desirable to use it again this spring? A: If your lawn has thin grass or if neighboring lawns were full of crabgrass last year, it might be a good idea to use the preventer as insurance. Some of the seed may have blown over into your yard.