Q- My sweet corn didn't do much last summer; most of the ears didn't fill out. What could have been the cause?

A- That's usually due to poor pollination. Plant the corn in three or four rows this year for better pollination.

Q- Is it necessary to have the soil in my vegetable garden tested every year or more often?

A- Once every two or four years is adequate, depending on several factors, according to specialists. When you have your soil tested, be sure the sample is a true compostite or representative sample. If the sample is not representative, it would be better if the soil test were not made, because the results will be inaccurate in determining the amount of lime and fertilizer to apply.

Q- Something's seriously wrong with my hemlock tree, as you can see from this specimen. Can you tell me what it is?

A- The problem is scale insects, Fiorinia hemlock scale. The males are white, the females yellowish with a slight tinge of brown, and the young are lemon yellow. They feed on the underside of the needles. There are two generations a year. A seriously infested tree has unhealthy - looking foliage: Needles turn yellow and drop prematurely. The vigor of the tree is greatly reduced and when infestation is permitted to continue, areas such as the crown or all of the tree may die. The scale may be controlled with dormant oil in late winter or early spring, or with Cygon used (in Maryland) between June 5 and 10 and between August 15 and 25. This is when the crawlers (new generation) appear. Directions on the label for mix and application should be followed closely.

Q- I simply cannot get impatiens seeds to come up after sowing them. I've been trying for several years with no luck. What's the secret?

A- The seeds need light to germinate, they should be kept evenly moist, the temperature should be around 70 F and it takes 15 to 20 days for germination.

Moisture is one of the most critical factors: Seeds covered lightly with fine sand or vermiculite usually germinate better and more evenly those left uncovered. The covering material should be just enough to barely hide the seed. The moisture helps prevent stress, which occurs when the sun and high temperatures dry out the soil surface. When seeds are covered too deeply, light is excluded and they may not germinate. The use of cold water will drop soil temperatures and result in lower and prolonged germination.

Q - Our lawn is literally covered with dandelions. Is it true they're good to eat?

A - In the spring, dandelion greens make a tasty salad when blanched, chilled and served with dressing, according to the National Geographic Society. They are also widely used as potherbs. Gourmets advise cutting the leaves while young, since they grow bitter with age. Many swear by a dandelion infusion as a spring tonic and blood purifier. Dandelion greens are rich in vitamins A and B, protein, calcium and phosphorus, the Society says.

Q - We have a tulip tree, and for the past three summers the leaves have been spotted and constantly falling off. Can you tell me what is wrong?

A - The tulip tree is subject to a fungus disease that causes large brown irregular blotches on the leaves. There is no good preventive control, other than picking up the leaves that fall and getting rid of them.

Q - What is a starter solution? My neighbour uses it and says he gets ripe tomatoes a week or two sooner because of it.

A - A starter solution is fertilizer high in phosphorus such as Plantabbs (11-15-20) or Miller's VHPF (6-25-15), dissolved in water and applied when the plant is planted outdoors, a glassful per plant. The phosphorus can counteract high and low soil temperatures that tend to restrict plant growth. At low phosphorus levels, a soil temperature varying only a few degrees from 59 F significantly inhibits growth. Some of the benefits are earlier maturity, higher quality and greater yields.

Q - I pruned my grape vine in early April, and now it's bleeding badly. Is there anything I can do to help it?

A - This loss of sap is in no way similar to the bleeding of humans. The liquid lost is little more than water and does no harm. There is no practical way to treat the wound to stop the bleeding. It will stop of its own accord in a short time.

Q - The flowers on my tulips were much smaller this year than last year; should I have dug them up and stored them?

A - After tulips have bloomed in the spring, the old bulb disintegrates, and in its place several new ones of various sizes develop. The new bulbs are not as large as the old ones and don't provide as good flowers. If tulips are planted eight to ten inches deep, there's less increase of new bulbs and the ones that do develop are better able to produce larger blooms the following year. Cutting off faded flowers to prevent seed formation will help toward larger bulbs and better flowers.

Q - Is there a biological way to prevent crabgrass without having to apply a weedkilling chemical?

A - Grass cut at a height of 2 1/2 inches will most likely have much less crabgrass than grass cut 1 1/2 inches. Germination of crabgrass seed and other weeds will not occur unless the soil surface gets some light, and a tall dense stand grass will reduce weed invasion.

Q - The soil we have dug for our garden is mostly clay. We have applied fertilizer and lime, but wonder if our efforts will be futile considering the type of soil we have. Also, in one or two spots there are some large roots that are just impossible to dig up. Will they harm the garden in the event it does produce?

A- The main problem with clay soil is drainage to the roots. Mixing an inch of compost, or Michigan peat or something similar with the top six inches of soil will help with that. The only damage the tree roots can do is compete with the garden plants for moisture and nutrients. If that seems to be happening, apply enough for all.

Q - I planted a Japanese red maple three years ago and it doesn't seem to have grown even an inch since then. Is there a way to speed up its growth?

A - When one of these trees has been transplanted, it sometimes takes two or three years for it to fully recover and start growing again. There are many varieties of Japanese maples and most of them grow very slowly. Some may take ten years or longer to reach a height of six to eight feet. One of the most important things is to water them regularly during prolonged dry weather. CAPTION: Illustration, no caption