USING HIGH TUNNELS TO EXTEND THE RASPBERRY SEASON INTO LATE FALL

Abstract

The use of high tunnels is a technology that can be implemented just about anywhere for a modest cost, and can be used to bring crops on earlier or extend them later in the season. Raspberries are a high value crop that, in season, sell for more than $3.00/lb. In the middle of winter, raspberries can sell for more than $10.00/lb. Our goal was to produce raspberries in October and November, after the field season ends from frost and rain, and when the selling price of raspberries doubles. Our project examined primocane-fruiting varieties and methods of managing plants to delay their production beyond the normal late August-September season. The first part of the study was to monitor the growth and productivity of several late varieties that typically fruit too late for the New York climate. One selection (NY01.64) and one cultivar (Josephine) appeared very promising for high tunnel production. The second set of treatments manipulated `Heritage' so that it fruits later than the normal September season. The five treatments were an unmanipulated control, applying straw over plots in late February at the rate of 6 tons/acre after a period of cold weather, mowing canes to the ground in early June shortly after they emerge, pinching primocanes (removing the top 4–6 inches) when they reach a height of about 2½ ft, and pinching when canes were 3½ ft tall. Each of these 4 treatments delayed flowering and shifted production to later in the season. The late pinching treatment appeared to provide the best yield curve under the high tunnel.