Q. I have planted zucchini for the past three years. The plants start out nicely, bloom well, produce a few squash, but then the vines begin to wilt. After 4 or 5 days the plants have flopped completely. We can find no bugs on any of the leaves. What's wrong?
A bacterial wilt sometimes causes plants to flop suddenly, but your problem more likely is squash vine borer, since you describe the wilting as taking 4 or 5 days.
The trick is to spray at the right time, about when the buds form, then two times, seven days apart. Mark this on your gardening calendar for next year.
Late June and early July are when the moth (which looks like a wasp) lays eggs on the stems near the base of the plant. If you catch borers in the stem just as the plant starts to wilt, you can make a slit and dig them out. The stem can then be covered with soil to form new roots.
Look for mushy sawdustlike material at the base of the plants for telltale evidence of borers.
Clean up all debris without delay and either burn it or send it to the dump in sealed bags. Deep plowing in the spring will help get rid of the pest. Also, plant squash in a completely different spot each year, if possible.
Q. We moved to a new home site last spring and, to our delight, the property has several pear trees. We picked the fruit just as soon as it ripened and it was delicious, yet the pears did not keep well. Within a few days after picking they turned to mush. Why?
Pears are fruit that should be picked while they are still in the green stage and before they have developed their best flavor. Most varieties should be picked just as soon as the stem will separate from the branch. Lift the fruit upward and give it a slight tug.
Q. We have two grape vines which form an arbor and have always had plenty of fruit both for eating and for jam. This year, however, wasps got into nearly every bunch. Is there some kind of repellent that we could use next year to deter the wasps?
Many folks have complained of heavy wasp populations this year.
Yes, wasps can be a nuisance, but usually they do little damage unless the fruit has become overripe or started to pop open because of heavy rain after a dry spell. The pulp expands faster than the skin, thus causing cracks. Bees and wasps are attracted to the sweet juice.
Clusters may be somewhat protected by slipping cut-up lengths of pantyhose over the fruit and closing the ends with twist-ties.
If the fruit is nearly ripe, it should be picked before the wasps have a chance to do any damage.
Q. We have a lovely backyard with some oak trees spaced just far enough apart that we could naturalize some daffodils between them, but we don't know quite how to go about it. Do the bulbs need to be fertilized? How deep and how far apart should they be planted? Is 6 hours of sunlight a day enough?
When naturalizing bulbs, be prepared to omit mowing those areas until the leaves have turned yellow in the spring. This allows the bulbs to recoup for next year's show.
Plant the bulbs in clusters (landscapers call them drifts), rather than spacing single bulbs evenly over the area. To help calculate your bulb needs, assume clusters to be 10 to 24 bulbs, with individual bulbs 6 to 8 inches apart and about 6 inches deep. These clusters can be randomly spaced, depending upon the terrain and other plants in the area.
It's much easier to apply fertilizer over the top of the soil after planting (watering in the dry type). Use about 2 pounds of balanced dry fertilizer per 100 square feet (or liquid, according to the directions on the container).
A scattering of bonemeal or superphosphate at the same rate as dry fertilizer will enhance the blooms.
Bulbs tolerate almost any type of soil that is well drained. Six hours of sunlight is sufficient. Work up all areas to be planted before laying out the bulbs.
Q. Several Christmases ago I received a little evergreen tree, which I repotted. It grew rather nicely until it became covered with a sprinkling of sticky, cottony flecks. Thinking it might have become too crowded or that it might be due to something in the soil, I disposed of the tree. I received a similar tree at holiday time a year later. I transplanted it as it grew, until it now occupies a large wooden tub. Now it also has the same sticky, cottony stuff. What is it and how do I get rid of it?
Your evergreen has mealybugs, a common pest of houseplants (and outdoor plants in mild climates).
Each little cottony puff has a waxy coating to protect the tiny insect underneath. These suck the juice from the plant and exude the sticky substance. At a certain stage (the crawler stage) the insect becomes very mobile and can attach itself to someone's clothing while hitching a ride to an unsuspecting person's plant.
For a pesticide, use the all-purpose formula for houseplants. To a gallon of water add 1 tablespoon each of liquid household detergent and hot pepper sauce. Add 1 cup of rubbing alcohol. Spray thoroughly, covering both the tops and bottoms of the branches until they're dripping wet. Repeat at 7-day intervals until the infestation is eradicated.
Q. Is it all right to use the spent charcoal from a grill on our vegetable garden? Soil in our area is very heavy and it seems as if the charcoal would be beneficial in loosening up the soil.
If the fuel used in your grill is real charcoal, then it is beneficial to use in the garden. There would be a scant amount of nutrients, but, as you suggest, the value would be as a soil conditioner. However, if you use briquettes, then you should not use them on the garden since they contain material that is toxic to plants.