Extension News

Ask the ISU Experts

Note to media editors:

Got gardening questions? Contact the Hortline at (515) 294-3108 (Monday-Friday; 10 a.m.-12 Noon and 1-4:30 p.m.) or send an e-mail to hortline@iastate.edu. For more gardening information visit us at Yard and Garden Online at www.yardandgarden.extension.iastate.edu.



What can I do to prevent my tomatoes from cracking? 
Fruit cracking is common problem on tomatoes. Fruit cracking is associated with wide fluctuations in soil moisture levels. A heavy rain or deep watering after a long, dry period results in rapid water uptake by the plant. The sudden uptake in water results in cracking of ripening fruit. Generally, fruit cracking is most common on the large, beefsteak-type tomatoes. 

Fruit cracking can be reduced by providing the tomato plants with a consistent supply of moisture during the summer months. During dry weather, a thorough soaking once every seven days should be adequate for most tomato plants. Conserve soil moisture by mulching the area around tomato plants with dry grass clippings, shredded leaves, straw or other materials. Also, plant tomato varieties that possess good crack resistance. Tomato varieties that possess good to excellent crack resistance include ‘Jetstar’ and ‘Mountain Spring.’ 

Will it harm the turfgrass to fertilize the lawn when it’s dormant? 
Fertilizing a brown, dormant lawn will not harm it. However, the turfgrass may not receive the full benefit of the fertilizer application.  If a granular fertilizer remains on the soil surface because of a lack of rain, some of the material may actually volatilize into the air.  It probably would be best to wait until the grass begins to green back up again before fertilizing.  September and late October/early November are excellent times to fertilize Kentucky bluegrass lawns in Iowa. 

When should I harvest sweet corn? 
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. An immature ear will not be completely filled to the tip and the kernels produce a clear, watery liquid when punctured. 

The harvest date can be estimated by noting the date of silk emergence. The number of days from silk emergence to harvest is approximately 18 to 23 days. Prime maturity, however, may be reached in 15 days or less if day and night temperatures are exceptionally warm. Most hybrid sweet corn varieties produce two ears per plant. The upper ear usually matures one or two days before the lower ear. 

Harvest sweet corn by grasping the ear at its base and then twisting downward. Use or refrigerate sweet corn immediately after harvest. Optimum storage conditions for sweet corn are a temperature of 32 degrees F and a relative humidity of  95 percent.


Contacts :

Richard Jauron, Horticulture, (515) 294-1871, rjauron@iastate.edu

Jean McGuire, Continuing Education and Communication Services, (515) 294-7033, jmcguire@iastate.edu