It's raspberry season in many parts of the country. If you love red raspberries and want to get an even bigger crop, consider using a technique developed by researchers in Norway. They grew two red raspberry varieties in greenhouses and outdoors. Plants were grown the first season, then moved to cold storage until the following spring. All of these second-year plants were tip pruned to a height of 5 feet on June 1st and planted either in an open plastic hoop house or outdoors. The highest yields (up to 8 pounds of berries per cane) were achieved on raspberries grown in the plastic hoop house. Yields of plants grown outdoors were lower.
Researchers believed of all the factors influencing production, the tip pruning height was the most important. For gardeners in northern climates, growing raspberries in hoop houses and tip pruning second year canes to 5 feet might be the ticket to higher yields.
For more information on this pruning and growing system, go to: Science Direct.