Frequently Asked Questions

Question:
Why are some of the fruit on my summer squash misshapen?
Answer:

Misshapen fruit may develop if pollination is inadequate.   When pollination is incomplete, the fruit develops unevenly because the ovary wall enlarges more adjacent to fertilized seeds.  Inadequate pollination may be due to low...

Question:
What kind of yield can I expect from blueberries?
Answer:

Blueberry plants should come into full production by the fifth or sixth year.  Gardeners can expect to harvest 5 to 10 pounds of fruit per plant from mature highbush blueberries.  Half-high blueberries generally produce 1 to 3 pounds...

Question:
There are small, white objects resembling kernels of popcorn on the branches of my silver maple tree. What are they?
Answer:

The small, white, popcorn-like objects are likely cottony maple scale.  Cottony maple scale is an insect.  It is most commonly found on silver maple trees.  However, it can also be found on other maples, oak, linden, hackberry,...

Question:
How often should I water my garden?
Answer:

The frequency of watering is determined by soil characteristics, weather conditions, type of plant material, and other factors.  In general, however, a deep watering once a week in dry weather should be adequate for most fruit, vegetable,...

Question:
When is the best time to water the garden?
Answer:

Early morning (5:00 to 9:00 am) is the best time to water the garden when using a sprinkler, garden hose, or any other device that wets the plant foliage.  When watering is completed, the plant foliage dries quickly.  The rapid drying...

Question:
Are there ways to reduce water use in the garden?
Answer:

Apply a mulch around landscape plantings and garden areas to conserve soil moisture.  Mulching reduces the rate of evaporation from the soil surface and also limits weed competition.  Organic materials, such as grass clippings, clean...

Question:
What is responsible for the yellow spots on my crabapple leaves?
Answer:

Cedar-apple rust is likely responsible for the yellow spots on the crabapple leaves.  Cedar-apple rust is a fungal disease.  The fungus  requires both a crabapple or apple and a cedar (juniper) to complete its life cycle. Crabapple...

Question:
The leaves on my sycamore have a bleached appearance in late summer. Why?
Answer:

The bleached appearance may be due to lace bugs.  Lace bugs are sap feeding insects commonly found on the leaves of shade and ornamental trees in Iowa.  The most commonly affected trees are hackberry, sycamore, and oak.  Adult lace...

Question:
A small greenish worm is eating the foliage on my cherry tree. What should I do?
Answer:

The greenish worm is probably the pear slug.  The pear slug is not an actual slug.  It’s the larval stage of an insect (sawfly).  The pear slug feeds on pear, cherry, plum, and several other woody plants.  

The slug-...

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:
When should I harvest cucumbers?
Answer:

Harvest cucumbers every 2 to 3 days and promptly pick the fruits when they reach the desired size.  Pickling varieties should be harvested when the fruits are 2 to 4 inches long.  Slicing cucumbers should be 6 to 8 inches long and 1.5...

Question:
How can I control powdery mildew on my garden phlox?
Answer:

Powdery mildew is a common disease of garden phlox (Phlox paniculata).  The fungal disease produces a grayish white coating on the leaves.  Infected leaves eventually turn yellow and then brown.  Initial symptoms appear on...

Question:
The ears on my sweet corn are poorly filled. What are possible causes?
Answer:

Poorly filled ears are usually the result of poor pollination.  Hot, dry winds and dry soil conditions may adversely affect pollination and fertilization and result in poorly filled ears. Water sweet corn during pollination if the soil is...

Question:
What would be a good planting site for the magic lily?
Answer:

The magic lily (Lycoris squamigera) is a rather intriguing plant.  Other common names include resurrection lily, surprise lily, hardy amaryllis, and naked lady.  The life cycle of Lycoris squamigera is different from...

Question:
What is the proper way to harvest and store popcorn?
Answer:

The moisture content of popcorn determines its popping quality.  The ideal moisture content of popcorn is 13 to 14.5 percent. 

Popcorn should be left on the stalk until fully mature.  Harvest the ears when the husks are...

Question:
How do I control bagworms on my spruce tree?
Answer:

Bagworms are caterpillars that live inside spindle-shaped bags.  (The bags somewhat resemble small Christmas tree ornaments hanging from the tree.)  Bagworms feed on the foliage of a wide variety of trees and shrubs.  However, they...

Question:
How should I water a newly seeded lawn?
Answer:

After seeding, keep the upper 1 inch of soil moist by watering once or twice a day.  With adequate moisture and warm soil temperatures (55 degrees Fahrenheit or above), the seeds of most turfgrasses should germinate in 2 to 3 weeks....

Question:
Is it safe to plant currants and gooseberries in home gardens in Iowa?
Answer:

Early in the 1900's, white pine blister rust (Cronartium ribicola) became a serious disease problem in the United States.  White pine blister rust requires both a currant or gooseberry (Ribes species) and white pine to...

Question:
The leaves on my river birch are yellow-green. Why?
Answer:

In Iowa, the foliage of the river birch (Betula nigra) often turns a sickly yellow-green. The yellow-green foliage is due to a deficiency of iron. The problem is referred to as iron chlorosis. (A close examination of chlorotic leaves...

Question:
How can I avoid drift problems when applying a broadleaf herbicide to my lawn?
Answer:

Before applying any herbicide, carefully read and follow label directions.  When applying liquid formulations, potential spray drift problems can be avoided by following simple precautions.   Don’t spray when winds exceed 5 mph....

Question:
What are some good raspberry varieties for Iowa?
Answer:

Suggested raspberry varieties for Iowa include:

Summer-Bearing Red Raspberries for Iowa

  • ‘Boyne’
  • ‘Latham’
  • ‘Killarney’

Fall-Bearing Red Raspberries for Iowa

...
Question:
How do I preserve cockscomb?
Answer:

Air-drying is the best way to preserve cockscomb.  After harvesting cockscomb, strip the foliage from the stems.  Tie the stems into small bunches with rubber bands.  Hang the loose bunches upside down in a warm, dry, well-...

Question:
When can I harvest eggplant?
Answer:

Begin harvesting the large, oval varieties when the fruit are 2 inches in diameter.  Continue to harvest the fruit until they are 4 to 6 inches across.  At the proper harvest stage, the fruit will be firm and shiny.  Overmature...

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:
How can I keep raccoons out of my sweet corn?
Answer:

The most effective way to prevent damage to the sweet corn crop is to encircle the area with an electric fence.  A two-wire fence with one wire 4 to 6 inches above the ground and the other at 12 inches should keep the raccoons out of the...

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