MSU Extension

Editor’s note: This article is from the archives of the MSU Crop Advisory Team Alerts. Check the label of any pesticide referenced to ensure your use is included.

This article was initially published in The Vegetable Growers News April 2006 issue P23-24.

Records as early as 1927 show Michigan as the leader in United States pickling cucumber production. In 2005, Michigan pickle production was valued at over $35 million. Michigan’s dominance in the pickle industry is the result of many factors, including use of high quality seed, good agronomic practices, and mechanical harvesting. Once over mechanical harvesting is without a doubt the single most important factor that improved pickling cucumber production in Michigan. This technology has reduced the labor inputs needed for multiple hand picks and, most importantly, significantly increased planting densities. Until 1948, theUSDA recommendation for pickling cucumber spacing was 6 to 7 feet between rows and 3 to 4 feet between plants in the row, for a planting density of 1,500 to 2,500 plants per acre. In contrast a 2003 Michigan survey found spacings as close as 12 inch rows with 4 inches between plants within the row (about 130,000 plants/acre) were being used successfully.

The need for high planting densities

Before mechanical harvesting, pickling cucumber was grown at low densities and yield was maximized by multiple hand picks. In machine -harvested cucumber production systems: however, all plants are harvested destructively when they average 1 to 1.5 fruit per plant. Under such a system, yield is maximized by increasing plants per acre rather than number of fruits per plant. High densities are achieved by reducing between and in row plant spacing. In 2003 and 2004, we conducted an experiment with a total of 12 densities using combinations of 4 row spacing s (12, 18, 24 and 30 inches) and 3 plant spacing s inside the row (4, 5, and 6 inches). Spacings were selected based on current practices in Michigan and to achieve specific plant populations. We found that number of fruits per plant quickly becomes a limiting factor for yield increase at low planting densities. Even though increased planting density reduces the total number of fruits per plant, the total number of fruit per acre increases. Maximum yield was found at a density of about 130,000 plants/acre. Beyond this density, competition among cucumber plants becomes a limiting factor and can result in significant yield reduction.

Maximize economic value not yield

If seed were free, then planting densities with the highest yield would also produce the highest economic (dollar) value. However, profitability of pickling cucumber is not just a function of total fruit weight but is also dependent on seed cost and selling price. Therefore, seed cost should be included in the analyses of studies designed to identify optimum pickling cucumber densities. In our economic analysis we used an average cost of $1.65 per thousand seeds and a selling price of $3.25 per bushel for grade 2 and 3 (marketable grades for machine-harvested cucumbers). Economic value was obtained by multiplying yield by selling price and subtracting seed cost. We found optimum planting density required to maximize economic value was significantly lower than that required to maximize yield. With a 5% margin of error, optimum economic value is obtained with densities between 72,000 and 120,000 plants/acre. Optimum density for highest economic value varies depending on seed cost and cucumber selling price. The higher the seed cost the lower the optimum density. Also the lower the selling price the lower the optimum density. For pickle production to be a viable business, growers must use planting density as a tool to maximize economic value instead of to maximize yield.

Other factors that should be taken into account when selecting pickling cucumber planting density include: cultivars and growing conditions. We used the cultivar Vlaspik with indeterminate growth habit. Other cultivars, especially those with determinate growth habit, would respond differently. Growing conditions (especially fertilization), pest management, irrigation, and harvester efficiency also impact optimum planting density. Finally, experienced growers will maximize economic value at a specific planting density through adequate timing of harvest.