An asparagus planting may produce good crops for 15 to 20 years when good cultural practices are followed. The first chore in the spring is to cut off the dead asparagus tops at ground level. Early spring is also an excellent time to fertilize the asparagus planting. Apply 50 pounds of barnyard manure per 100 square feet. Lightly till the manure into the top 2 or 3 inches of soil with a rototiller or spade. This must be done in early spring before the asparagus starts to grow. If manure is unavailable, apply 1 to 1 1/2 pounds of a balanced fertilizer, such as a 10-10-10 or 12-12- 12, per 100 square feet in the spring.
Weed control efforts in the spring are also crucial. The best way to control weeds is to periodically hoe or till the planting. Cultivate lightly to avoid damage to emerging spears. Tough perennial weeds, such as quackgrass, can be effectively controlled by applying Roundup (glyphosate) to the weeds immediately after the last harvest of the season.
Begin harvesting the asparagus spears when they are 6 to 8 inches long. Harvest by cutting or snapping the spears at ground level. During the harvest season, removal of all the spears or "clean cutting" is recommended. Allowing some of the spears to continue to grow and produce fern-type growth inhibits the development of new spears. Stop harvesting established asparagus by mid-June.
This article originally appeared in the March 24, 1993 issue, p. 28.
Links to this article are strongly encouraged, and this article may be republished without further permission if published as written and if credit is given to the author, Horticulture and Home Pest News, and Iowa State University Extension and Outreach. If this article is to be used in any other manner, permission from the author is required. This article was originally published on March 24, 1993. The information contained within may not be the most current and accurate depending on when it is accessed.