Frequently Asked Questions

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 frequently should I water annuals in containers?
Answer:

The frequency of watering may vary considerably from container to container.  Watering frequency depends on the size and type of container, composition of the potting mix, plant species, and weather conditions.  Some plants, such as...

Question:
How do I know when a watermelon is ready to harvest?
Answer:

Harvest watermelons when the underside or belly of the fruit turns from a greenish white to buttery yellow or cream.  This color change is especially pronounced on the dark green skinned varieties.  In addition, the fruit tends to lose...

Question:
The foliage on my bleeding heart dies back in early summer. What is wrong?
Answer:

The common bleeding heart (Dicentra spectabilis) typically dies back in mid-summer in Iowa.  However, plants may die back in late spring or early summer if growing conditions are not favorable.  The common bleeding heart...

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:
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,...

Question:
I have some small, purplish spots on the canes of my black raspberries. What is it and how can it be controlled?
Answer:

The small, purplish spots are most likely due to anthracnose.  Anthracnose is a serious fungal disease of raspberries, especially black raspberries.  The disease is readily recognized by the small, purplish spots that develop on young...

Question:
How often should I water bee balms?
Answer:

Bee balms like an even supply of moisture during the growing season.  For best performance, water bee balms every 7 to 10 days during dry periods.  When watering, soak the soil to a depth of 6 to 8 inches.  Apply a mulch around...

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:
When can I divide lungworts?
Answer:

Lungworts (Pulmonaria spp.) can be divided in late summer/early fall or after flowering in spring.  Carefully dig up the entire clump, then divide the clump into sections with a sharp knife.  Each section should contain several...

Question:
Is it possible to pick green tomatoes before the first frost and ripen them indoors?
Answer:

Yes, green tomatoes can be ripened indoors.  Just before the first frost, remove all mature, greenish white fruit from the vines.  They should be solid, firm, and free of defects.  Remove the stems, then clean and dry the fruit....

Question:
Do I need to add an activator to my compost pile?
Answer:

It is not necessary to add an inoculant or activator to a compost pile. A compost pile should be composed of layers of plant material and soil or finished compost. The soil and finished compost contain the microbes that will decompose the plant...

Pages