Although Iowa has never ranked high among the states as a producer of asparagus for market or canning, the asparagus acreage planted, particularly by canners, is increasing.
No exact information is available concerning the effect of the cutting season’s length upon yields over a period of years. Market gardeners usually stop cutting asparagus in Iowa between June 1 and June 15. The demand for asparagus at this time decreases and the prices drop too low for profitable harvesting. To prevent damage to future yields, June 15 also appears to be the latest safe harvest date, though no substantiating experimental data have been available. Canners, however, could harvest asparagus later than June 15 profitably if such treatment did not injure the yield and quality of the future harvests.
Haber, E. S.
"Effect of harvesting, spacing and age of plants on yields of asparagus,"
Bulletin: Vol. 30
, Article 1.
Available at: https://lib.dr.iastate.edu/bulletin/vol30/iss339/1