Trellising and Plastic Mulch Effects on Cucumber Production in High Tunnels

Cucumbers (Cucumis sativus L. ‘Dasher’) are summer vegetables but are extremely frost-sensitive. Most vegetable growers in Iowa and other Midwestern states are exploring ways to start the crop early in the spring. One method to extend the production season and start early production of cucumbers is using a high tunnel. Although high tunnels are extremely useful in the spring to increase temperature, managing summer temperatures in them is a challenging task. This study investigated the use of plastic mulch color and trellising system to manage high temperatures in a high tunnel cucumber production system. The experimental design was a randomized complete block with four replications. Treatments comprised of: 1) black plastic mulch; 2) black plastic mulch + trellis; 3) white plastic mulch; and 4) white plastic mulch + trellis. Cucumber plants were transplanted on raised beds covered with black or white plastic mulch on May, 18, 2012. Data was collected on soil temperature, reflected light intensity off the plastic, crop yield, and fruit quality. Color of plastic mulch modified soil temperature at four inch depth. Average daily soil temperature was higher in the black plastic mulch as compared to white. Reflected light intensity was 44% higher from the white plastic mulch as compared to black. There were no significant differences in marketable number of cucumbers between black or white plastic mulches, however, within each mulch treatment, trellis treatment significantly increased yield over non-trellised treatment. The marketable numbers were almost one and a half times more when trellis system was used. Marketable weight followed the same pattern. There was no difference in marketable yield between trellised treatments of black or white plastic mulch. Non-marketable fruit weight was highest in trellised treatment, irrespective of plastic color. Fruit quality attribute with respect to average fruit length was highest in the black plastic mulch + trellis treatment. Results from this study indicate that trellising cucumbers in high tunnel production systems affects fruit length and yield higher number of marketable fruits as compared to non-trellised systems. Trellising allows for better air movement and heat dissipation and reduces the occurrence of fungal and bacterial diseases. Although white plastic mulch reflected almost double the amount of light when compared to black, it did not translate to enhanced yield or productivity. White plastic mulch kept the soil cooler than black and could be used in high tunnel production when crop plantings occur during peak summer.