Frequently Asked Questions

Question:
There is a pile of sawdust-like material at the base of a large tree. What could be the problem?
Answer:

It’s likely the pile of sawdust-like material was produced by carpenter ants.  Carpenter ants commonly nest inside older, hollow trees or in trees with dead limbs or branches.  Carpenter ants do not eat wood.  However, they...

Question:
When should I harvest garlic?
Answer:

Harvest garlic when the foliage begins to dry.  In Iowa, garlic is usually harvested in August or September.  Carefully dig the bulbs with a garden fork or shovel.  Dry the garlic in a warm, dry, well-ventilated location. ...

Question:
My apple trees have set a heavy crop of fruit. Do I need to thin the fruit?
Answer:

Apple and other fruit trees occasionally set too many fruit.

Thinning is necessary to:

  1. Obtain large, high quality fruit at harvest.
  2. Allow development of flower buds for next year’s crop, thus overcoming the tendency...
Question:
What effects will construction activities have on nearby trees?
Answer:

Construction of buildings, patios, garages, driveways, sidewalks, and roads often compromises the growing environment of nearby trees.  The majority of a tree’s roots are located in the top 12 to 18 inches of soil and often extend well...

Question:
How do I get rid of moss in my lawn?
Answer:

Mosses in lawns are usually a sign of poor growing conditions.  Turfgrasses have a difficult time growing in heavy shade, compacted soils, or other poor sites.  However, mosses are adapted to a wide range of environmental conditions....

Question:
How can I keep birds from eating my grapes?
Answer:

The best way to prevent birds from eating the grape crop is to place netting over the grapevines.  Netting can be purchased at garden centers or through mail-order companies.  When placing netting over the grapevines, make sure the...

Question:
Are marigolds pest free?
Answer:

While marigolds are seldom bothered by insects and diseases, they are not problem free.  Spider mites can devastate marigolds in hot, dry weather.  Grasshoppers can also cause considerable damage.  Aster yellows is an occasional...

Question:
How do I control weeds in my strawberry patch?
Answer:

Weed control is essential to insure optimal plant growth and fruit production.  Weeds compete with the strawberry plants for water, nutrients, and sunlight.  Weeds also reduce air circulation which results in fruit and foliage staying...

Question:
When can I divide garden phlox?
Answer:

Garden phlox (Phlox paniculata) can be divided in spring or late summer/early fall.  In spring, dig up the plants just as new growth begins to appear.  Divide each clump into sections with a sharp knife.  Each division...

Question:
I would like to grow onions for storage over winter. Which onion varieties are best for storage?
Answer:

The storage or keeping quality of onions is determined by the cultivar (variety), harvesting and curing procedures, and storage conditions. 

Longer Storage Life Varieties

  • ‘Copra’
  • ‘Sweet Sandwich’
  • ‘Red...
Question:
Can I put disease-infested plant material in my compost pile?
Answer:

Temperatures of 150 to 180 degrees Fahrenheit are required to kill most plant disease pathogens. Unfortunately, the internal temperatures of most home compost piles don’t reach this level and the disease organisms are not destroyed. For many home...

Question:
Several of my tomatoes are misshapen. Why?
Answer:

Misshapen (catfaced) fruit may be due to cool weather during fruit set.  Exposure to 2,4- D or similar broadleaf herbicides is another possibility.  Catfacing is most common on large-fruited tomato varieties.  Affected fruit show...

Question:
Rabbits have damaged several trees and shrubs in my yard. Can I do anything to save them?
Answer:

Deciduous trees that have been girdled (the bark has been removed completely around the trunk) have essentially been destroyed.  The best course of action is to replace the girdled trees.  Wrapping the trunk or applying pruning paint to...

Question:
How do you store garlic?
Answer:

After harvesting the garlic, dry the garlic in a warm, dry, well-ventilated location.  Place the garlic on an elevated wire screen or slotted tray to promote drying.  When the tops have dried, cut off the dry foliage 1 inch above the...

Question:
Can blueberries be successfully grown in Iowa?
Answer:

Blueberries can be successfully grown in Iowa.  However, they do have special growing requirements. 

Blueberry plants require a sunny location and a well-drained soil high in organic matter.  Avoid wet, poorly drained sites...

Question:
There are several large surface roots around my shade tree. Can I safely cover these roots with soil?
Answer:

Trees have shallow roots. The vast majority of a tree’s roots are located in the top 12 to 18 inches of soil.  As the tree roots grow, some of the larger roots near the soil surface may emerge from the ground. While many individuals regard...

Question:
How do I control nimblewill in my lawn?
Answer:

Nimblewill (Muhlenbergia schreberi) is a warm-season perennial grass.  Nimblewill is a thin, wiry grass that is pale green or gray-green.  It spreads by aboveground shoots or stolons, often forming circular spots in the lawn....

Question:
How can I prevent "bees" from damaging my grape crop?
Answer:

The bee-like insects are probably yellowjackets.  Yellowjackets are social wasps that build paper nests either in the ground, a log or landscape timber, or building wall or attic.  The workers from the colony travel up to a few hundred...

Question:
Can I keep rabbits out of my vegetable garden by planting marigolds around the perimeter?
Answer:

Marigolds do not repel rabbits, deer, or other animals.  In fact, rabbits occasionally browse heavily on marigolds.  Erecting a chicken wire or hardware cloth fence around the vegetable garden is the best way to keep rabbits out of the...

Question:
Grasses are taking over my strawberry patch. How can they be controlled?
Answer:

If the strawberry patch is being overrun with perennial grasses, such as quackgrass, control is not very practical.  Your best option would be to prepare a new site for a strawberry bed this summer or fall and plant a new bed next spring....

Question:
When can I transplant jack-in-the-pulpit?
Answer:

Jack-in-the-pulpit (Arisaema triphyllum) can be transplanted after the foliage dies back in late summer.  Jack-in-the-pulpit performs best in moist, organic-rich soils in partial to heavy shade.  The corm-like tubers should be...

Question:
When should you harvest onions?
Answer:

Onions should be harvested when most of the tops have fallen over and begun to dry.  Carefully pull or dig the bulbs with the tops attached.  

Question:
How can I accelerate the decomposition of leaves in my compost pile?
Answer:

Leaves contain high levels of carbon and small amounts of nitrogen. The microbes that decompose leaves and other types of organic matter require nitrogen for their own metabolism and growth. A compost pile composed mainly of leaves decomposes...

Question:
My tomatoes are developing white or yellow areas on the sides of the fruit exposed to the sun. Why?
Answer:

The white or yellow areas on your tomatoes are due to sunscald.  Sunscald occurs on fruit exposed to the sun during periods of extreme heat.  Initial symptoms of sunscald are the development of shiny white or yellow areas on the fruit....

Question:
Rabbits heavily damaged my raspberries over winter. Will they produce a crop this year?
Answer:

Purple, black, and summer-bearing red raspberries that have been badly damaged by rabbits will likely produce little fruit this year.  (Purple, black, and summer-bearing red raspberries produce fruit on the previous year's shoots. ...

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