Extension News

Ask the ISU Experts

Asparagus bed

Note to media editors:

Got gardening questions? Contact the Hortline at (515) 294-3108 (M-F; 10-12 & 1-4:30) 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


When and how do you plant an asparagus bed? 


Early spring (as soon as the soil can be worked in late March or April) is the best time to plant a new asparagus bed. Since a well-maintained asparagus planting may remain productive for 15 to 20 years, carefully consider possible sites. The site should receive full sunlight. Stay away from shady areas near buildings or large trees. Soil drainage is another important consideration. Asparagus prefers well-drained soils. In poorly drained sites, the plants eventually may die. A location at the north or east edge of the vegetable garden usually is a good site. 


Asparagus usually is established by planting asparagus crowns. Suggested varieties for Iowa include ‘Jersey Giant,’ ‘Jersey Knight,’ ‘Jersey King,’ ‘Mary Washington’ and ‘Purple Passion.’ Asparagus crowns are planted in shallow trenches or furrows. The planting depth depends on the soil type. The crowns may be planted 6 to 8 inches deep in light, sandy soils, but only 4 inches deep in heavier soils. A small amount of manure can be worked into the soil in the bottom of the trench before planting. Space the crowns 12 to 18 inches apart within the row. Rows should be spaced 4 to 5 feet apart. Spread the roots out in the trench with the buds pointing upward.  Finally, completely fill in the furrows.  (Though a common practice, it is not necessary to gradually fill in the furrows as the asparagus plants grow.) 


When should I apply a preemergence herbicide to my lawn? 


Preemergence herbicides are primarily applied to lawns to control crabgrass. Crabgrass is a warm-season, annual grass. It is a common weed in lawns and gardens. Crabgrass seeds germinate over several weeks from spring to early summer. 


The keys to successful control of crabgrass in lawns are correct timing of the preemergence herbicide application and proper application of the material.  Preemergence herbicides must be applied before the crabgrass seeds germinate. If the material is applied too early, crabgrass seeds that germinate late in the season will not be controlled. If applied too late, some crabgrass seeds will have already germinated. 


Preemergence herbicides should normally be applied in early to mid-April in southern Iowa, mid-April to May 1 in central Iowa, and late April to early May in northern areas of the state.  Weather often varies considerable from year to year in Iowa.  Accordingly, gardeners should make adjustments in the timing of the preemergence herbicide application.  If the weather in March and April is consistently warmer than normal, apply the preemergence herbicide early in the normal time period. Apply the herbicide late in the recommended time period if Iowa is experiencing a cold early spring. 


To insure the herbicide is applied properly, carefully read and follow the label directions on the package. Also, make sure the spreader has been correctly calibrated and is working properly. 


What is a good planting site for fruit trees? 


Selecting the proper planting site is critical when planting fruit trees in the home landscape.  While fruit trees can be grown on a wide variety of soils, good soil drainage is imperative.  Apples and other fruit trees do not tolerate wet soils. Fruit trees planted in poorly drained soils often die within a few years of planting. Most fruit trees grow well in fertile soils with a pH of 6.0 to 7.5. Because of space restrictions, planting sites often are limited in the home landscape.  Fruit trees require full sun. Select a site that receives at least eight hours of direct sunlight each day.   Avoid shady sites near large trees. 



Contacts :

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

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

There is one photo for this week's column.

AsparagusBed32906.jpg [1.6 MB]