Frequently Asked Questions

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:
I have a chokecherry that sends up suckers in the yard around it. Is there any way to stop it from suckering?
Answer:

Chokecherries (Prunus virginiana) and several other trees will send up shoots (suckers) from their roots.  Unfortunately, there is nothing the home gardener can do to prevent these trees from suckering. 

The best way to...

Question:
When is the best time to sow grass seed?
Answer:

Late summer (mid-August to mid-September) is the best time to establish a lawn from seed in Iowa.  Late summer seeding has several advantages over spring seeding.  The seeds of cool-season grasses germinate quickly in the warm soil of...

Question:
When should I harvest raspberries?
Answer:

Raspberries are ripe when the fruit are fully colored.  Also, ripe berries slip easily from their receptacles, which remain on the plant.  If possible, harvest in the early morning hours before heat builds up in the fruit. ...

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...

Question:
When should I harvest pears?
Answer:

Pears should not be allowed to ripen on the tree.  If the fruit are left on the tree to ripen, stone cells develop in the fruit, giving the pears a gritty texture.  Tree-ripened fruit also will be poorly flavored.  Harvest pears...

Question:
What are the black spots or blotches on my apples?
Answer:

The problem may be sooty blotch and flyspeck.  Sooty blotch and flyspeck are 2 different fungal diseases that often occur together on apples.  Sooty blotch appears as dark brown to black, ½ inch or larger smudges on the surface of the...

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:
What are the benefits of aerating the lawn?
Answer:

Aeration relieves soil compaction, improves water and nutrient movement in the soil, and prevents thatch accumulation.  Aeration improves the growing conditions for the turfgrass plants and results in a healthier, more vigorous lawn. ...

Question:
When should grapes be harvested?
Answer:

Grapes should not be harvested until fully ripe.  The best indicators of ripeness are color, size, and flavor. 

Depending on the variety, the berry color changes from green to blue, red, or white as the grapes approach maturity....

Question:
A large evergreen was partially uprooted in a storm. Can I save it?
Answer:

Tree roots are not as deep as most people imagine.  Most tree roots are located in the top 12 to 18 inches of soil.  While tree roots are quite shallow, they often extend out into an area that is 2 to 3 times larger than the crown area...

Question:
There are areas in my lawn where the grass is rather sparse. How do I fix these areas?
Answer:

The thin areas can be repaired by overseeding.  Overseeding is the sowing of grass seed into an existing lawn.  In Iowa, late summer (mid-August to mid-September) is the best time to overseed a lawn. 

Good site preparation...

Question:
The bottom of my black raspberry leaves are covered with an orange substance. What is it?
Answer:

The orange substance on your black raspberry leaves is orange rust.  Orange rust occurs on black and purple raspberries and most varieties of blackberries.  Orange rust does not occur on red raspberries. 

Orange rust...

Question:
My chrysanthemums get tall and lanky and flop over onto the ground in fall. What can be done to prevent this?
Answer:

Pinch newly planted and established mums from spring to mid-summer.  Remove the upper 1 to 2 inches of the shoots when the stems are 6 to 8 inches tall.  New lateral (side) shoots will develop along the stems.  Pinch again when the...

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.  

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