Participants in the WSU organic farm’s community supported agriculture (CSA) project received fresh asparagus in their weekly box for the first time this summer, thanks to the work of WSU undergraduate Brian Koepke.
Brian Koepke at the
WSU organic farm.
Under the direction of vegetable extension specialist Carol Miles and organic farm manager Brad Jaeckel, Koepke looked at cropping practices – from soil amendments to cutting methods and regularity – and succeeded in extending what has been a 3-week harvest period to one that lasted nearly 10 weeks.
“Five-year-old crowns should have an eight- to ten-week harvest period,” said Koepke, an organic agricultural and food systems major who transferred to WSU from Hawaii.
Funded with a grant from the College of Agricultural, Human and Natural Resource Sciences academic programs department, Koepke’s project focused on the asparagus beds at the organic farm, where 150 Jersey knight asparagus crowns were planted in 2005. Another 30 crowns were planted in 2006.
Koepke worked in 18 separate 20-foot plots in three different asparagus beds. He started by looking at soil fertility in the beds, which to date had only been amended with compost. Soil samples showed the soil in all three beds was deficient in both nitrogen and sulfur. For comparison, he treated three replicated plots with only compost, three plots with a low rate of nitrogen, and three with a high rate of nitrogen.
He took a similar approach to harvesting methods three plots were harvested by snapping off spears by hand, three were harvested using a sharp knife, and three were harvested with a custom-made two-pronged asparagus harvester that is narrower than a traditional factory-made asparagus harvester.
In addition to comparing different methods, Koepke also looked at the regularity of harvest. He harvested every 24 hours, 7 days a week during the entire harvest period, except when spears did not grow to the desired length.
The results of Koepke’s project? He found that using the asparagus-harvesting tool allowed the spears to be cut at a longer length and with less damage to neighboring spears. He also found that harvesting every day during the peak of the season increased yields.
Overall, Koepke more than tripled the length of the harvest period as well as the yield, bringing in 72 pounds of asparagus to some very happy WSU organic farm CSA members.