Using high tunnels to produce blackberries organically in West Virginia

Using high tunnels to produce blackberries organically in West Virginia

Summary

The goals of this project are to evaluate the organic production feasibility of blackberries within and without a high tunnel. In 2008, 10 blackberry cultivars (12 plants/cultivar) were established in 3-gallon nursery containers filled with a mixture of peat moss and dairy manure compost. In spring 2008, the plants were potted and placed adjacent to the high tunnel and allowed to grow outside. Plants were watered regularly using pot drippers to supplement natural rainfall. No supplemental fertilizer was used during the establishment year. It was decided to grow the plants outside of the high tunnel before moving the pots into the high tunnel. The same varieties were established in organic-certified field plots.

All varieties except ‘Obsidian’ (a trailing type) survived establishment. ‘Obsidian’ developed a virus symptom which significantly reduced growth. Cane growth of potted plants (height, number and diameter) was significantly less relative to the field plots. Growing blackberries within containers is challenging. Plants required frequent watering within the pots. In later fall, the plants were moved into the high tunnel for overwintering and extended growth. A medium-weight row cover was placed over the plants until March. The following spring, the potted plants were removed from the high tunnel after bud-break. Plants were grown outside until flowering, upon which they were placed back within the high tunnel.

Since cane growth was poor, it was decided to increase the pot size to 7 gallons in year 2. Vigor was significantly low in 2009 in all the potted plants despite adequate watering and addition of soluble organic fertilizer. Perhaps blackberries do not grow well when the root system is constricted by containers.

At this point, it was decided to jettison container production and use blackberries as a ground planted crop within the high tunnel. In 2010, new blackberry cultivars were obtained and reestablished within the high tunnel.

Collaborators: