Asparagus is a high-value vegetable that is very well-suited to small-scale production in Missouri. If quality is good, both pre-picked and you-pick operations can be successful and profitable, with potential yields of 3,000 lbs. per acre possible. That said, it is difficult to understand why we do not have more asparagus growers in Missouri, especially when fresh, locally-grown asparagus is eagerly sought by consumers and tastes far superior to anything trucked in from California.

Probably the two main challenges for local growers are weed control and the need to irrigate for optimum yields. Information on which asparagus cultivars are best suited to our growing conditions is also lacking. A number of new asparagus cultivars have been released over the last 20 years, but they have not been extensively evaluated in the Midwest.

An asparagus planting of 0.7 acre was established at the Southwest Center in 1999. Seed from eleven modern asparagus cultivars (Table 1) was sown in the greenhouse on March 31, 1999. After deep plowing, liming, fertilizing, and disking the soil, the seedlings were transplanted into the field on June 7 and 25, 1999. Experimental plots consisted of three parallel 15-ft rows containing 12 plants per row, with two replicated plots per cultivar. Rows were 5 ft apart and separated lengthwise by alleys of 3.5 ft. Additional asparagus experiments (not described here) were also established at the same time within and among this cultivar evaluation so that it was spread out and interspersed over a large plantation area in a completely randomized design.

Harvest data were collected from all 36 plants per plot. The plots were allowed to become very well-established before initiating harvest during their fourth season in 2002, and continuing through 2004. Harvests were conducted April 15- May 1, 2002; April 15 - May 24, 2003; and April 9 - May 21, 2004. Spears were hand-harvested generally every two days during the harvest period, counted, weighed, and evaluated for quality. A statistical analysis was conducted to compare yields among the 11 cultivars.

Table 1 presents data on plot yields, including total weight and number of spears, as well as the calculated average weight per spear averaged over the 3-year trial. The cultivar ‘Jersey Deluxe’ was the overall 3-year champion, both in terms of total weight per plot and total number of spears. However, Jersey Deluxe’s average weight per spear was much lower than many other cultivars. The cultivar ‘Apollo’ produced the largest spears with an average of 10.6 g for all three years and 11.3 g during 2003 and 2004.

Statistically, we did not find true differences in total spear weight among cultivars, but did detect significant differences in number of spears per cultivar and average weight per spear. An interesting trend observed was that the cultivars producing the greater number of spears tended to produce smaller spears, and conversely, cultivars producing fewer spears were larger.

Yields in 2002 were poor because of a serious spring drought (we normally set up our irrigation system after spring harvest and were not well-prepared for a spring drought). The 2003 and 2004 yields, however, were excellent. Table 2 provides details on yields (converted to a pound per acre basis) of the eleven cultivars.

Including the poor 2002 yield data, the total calculated yield per acre of our best cultivar (Jersey Deluxe) was 1,788 lbs/acre. However, if we look only at 2003 and 2004 yields (realizing how important spring moisture is), our total yield was much better at 2,265 lbs/acre. At $3.00 per pound, this cultivar could potentially gross $6,795 annually per acre! I suspect that many growers could do quite a bit better than that as they would be focused solely on optimum production rather than on the various demands of the research trials that we were conducting.

We hope these results can assist potential asparagus growers, from back-yard gardeners to commercial growers, in choosing which asparagus cultivars to plant. But keep in mind that this was a relatively small study at a single location.

Furthermore, other important factors such as insect and disease resistance, flavor, tenderness, and earliness are not accounted for here. We would usually recommend planting more than one cultivar, especially on a large scale, to ensure genetic diversity in any type of horticultural planting.