Frequently Asked Questions

Question:
When should I apply a preventive type insecticide to control white grubs in the lawn?
Answer:

White grub populations and damage to lawns vary greatly from year to year and place to place, even varying from spot to spot within the same lawn due to variations in beetle numbers, weather, turfgrass vigor, soil conditions, and other factors....

Question:
Are black raspberries hardy in northern Iowa?
Answer:

Red and purple raspberries are hardy throughout the state.  Black raspberries, however, often suffer severe winter damage in northern Iowa and can be reliably grown only in central and southern portions of the state.  ‘Black Hawk’ (an...

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...

Question:
How do I care for a grapefruit tree?
Answer:

Grapefruit and several other types of citrus can be grown indoors in Iowa.  Indoors, place citrus plants in a sunny south or west window.  Water plants regularly when growing in spring and summer, less often in winter.  In spring...

Question:
How do I control weeds in my garden?
Answer:

Herbicides can be used to supplement cultivation, hand pulling, and mulches. 

Hand Pulling

Cultivation, hand pulling, and mulches are the primary means to control weeds in the home garden. 

Cultivation and hand...

Question:
There are big, hairy worms and tent-like structures in my walnut tree. What are they and how do I get rid of them?
Answer:

The “worms” are likely fall webworms.  Fall webworms are hairy, tan to yellow caterpillars.  As they feed, fall webworms construct tents or webs at the ends of branches.  Tents are initially small, but the caterpillars enlarge the...

Question:
How often should I aerate a lawn?
Answer:

The frequency of aeration is largely determined by the soil type and the amount of use.  Lawns growing in heavy, clay soils and those subject to heavy foot or pet traffic should be aerated twice a year.  Once a year should be sufficient...

Question:
I have several rows of grapevines. What would be a good cover crop between rows?
Answer:

Kentucky bluegrass is an excellent choice.  Bluegrass provides good cover, yet is less competitive than other cover crops.  Late summer (mid-August to mid-September) is the best time to establish bluegrass by seed.  Do not sow...

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:
There are round, circular spider webs are on my lawn. What should I do?
Answer:

The horizontal circular webs were created by various spiders collectively called grass spiders.  They are harmless to the grass and ecologically beneficial as predators.  The webs accumulate between rain showers and mowings.  They...

Question:
How can I tell dead canes from live shoots when pruning raspberries in late winter?
Answer:

Dead raspberry canes will be white to gray in color.  When dead canes are pruned, the tissue inside the stem will be tan to brown and dry.  Live canes will be brown to purple in color.  The tissue inside the stem will be white to...

Question:
How often should I water plants in hanging baskets?
Answer:

Plants in hanging baskets need to be watered frequently (especially in summer).  Potting mixes are light, well-drained, and dry out quickly.  Plus, hanging baskets may contain several plants.  In general, water plants in hanging...

Question:
How can you tell when a muskmelon is ripe?
Answer:

The fruit of the muskmelon or cantaloupe is mature when the stem slips easily from the melon with slight pressure.  The melon is not ripe if the stem has to be forcibly separated from the fruit.  Other indicators of maturity are based...

Question:
Can the butterfly weed be divided?
Answer:

The butterfly weed (Asclepias tuberosa) is a member of the milkweed family.  Plants grow 2 to 3 feet tall and produce flat-topped clusters of bright orange flowers from July through September.  Their flowers attract several...

Question:
When should I harvest sweet corn?
Answer:

Sweet corn should be harvested at the milk stage.  At this stage, the silks are brown and dry at the ear tip.  When punctured with a thumbnail, the soft kernels produce a milky juice.  Over-mature sweet corn is tough and doughy....

Question:
How long does it take a compost pile to break down?
Answer:

The rate of decomposition depends upon the composition of the compost pile, level of management, and other factors. A well-managed compost pile (one that is watered and turned regularly) containing a mixture of shredded plant material should be...

Question:
There are tan-colored, rough spots on the surface of my pear fruit. Is it possible to prevent this from occurring?
Answer:

Russeting is probably responsible for the tan-colored spots on your pears.  Russeting also develops on the surface of apples.  While affected fruit are not attractive, russeting doesn’t affect the eating quality of the fruit. ...

Question:
My magnolia is infested with magnolia scale. What are my control options?
Answer:

Magnolia scale is the largest scale insect in Iowa.  Sap feeding by the scales causes stress to heavily infested plants and can result in stunted growth, yellowish foliage, branch dieback, or death of the plant.  Magnolia scales produce...

Question:
What is the proper way to aerate a lawn?
Answer:

Aerate lawns with a core aerator.  Core aerators have hollow metal tubes or tines that remove plugs of soil.  Avoid spike-type devices that simply punch holes (compacting the soil) in the ground.  Core aerators are often available...

Question:
I have wort-like growths on the undersides of my grape leaves. What is it and does it need to be controlled?
Answer:

The wort-like growths on the grape leaves were probably caused by the grape phylloxera.  The grape phylloxera is a small, aphid-like insect.  The grape phylloxera has a complex life cycle that affects the leaves and roots of the...

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:
Large areas of my lawn have turned orange. Why?
Answer:

The orange color is likely due to rust.  Rust is a fungal disease.  It can be diagnosed by walking across the lawn in white shoes.  As you walk across the lawn, bright orange spores of the rust fungus will rub off onto the shoes,...

Pages