SUMMARY OF RESULTS
This grant showed that covering fall-bearing raspberries with a floating row cover was cost effective and did induce earlier raspberry harvest. Raspberries that were covered averaged 1,407 pounds per acre, whereas those that were not covered averaged 70 pounds per acre. Raspberries that were covered ripened nearly three weeks prior to non-covered raspberries.
We intended to determine if it is cost effective to cover fall-bearing raspberries with spun-bound polyester floating row cover. Fall-bearing raspberries produce on first-year canes; summer-bearing raspberries produce on second-year canes. The advantage of growing fall-bearing raspberries is that they will not suffer winter-kill because they bear fruit on first-year canes that never overwinter. Summer-bearing raspberries bear fruit on canes that grow vegetative during the first year and then bear fruit the second year. Unfortunately, during overwintering they often suffer damage during cold winters. The disadvantage of fall-bearing raspberries is that they produce late in the year and they seldom reach their full yield potential before frosts early in the fall stop growth.
Fall-bearing raspberries have never been harvested commercially in the Bear Lake Valley, but due to severe winter-kill producers would like to explore whether they will be profitable. This grant examines whether fall-bearing raspberries can be profitable in areas such as the Bear Lake Valley that have short growing seasons if the raspberries are covered in the spring.
The experiment consisted of four rows of fall-bearing raspberries, three of which were covered with a middle row left uncovered as a control. All of the rows were the same variety (Polana) and were planted in the spring of 2006.
We covered three rows on April 10, 2008, and by May 30, they were breaking through the floating row cover so the cover was removed. At that time, the average height of the covered rows was 23 inches and the height of the uncovered rows was 10 inches.
Throughout the summer, the uncovered row gradually appeared to catch-up to the covered rows in height. However, the uncovered row never achieved the same cane density as those that were covered. In addition, the fruit production of the covered canes began approximately August 25, whereas the uncovered canes never began producing significant amounts prior to suffering a frost that stopped ripening.
We measured the total production by adding the number of pounds harvested from each of the four rows.
Based upon the average price received for the raspberries in the Bear Lake Valley, the covered rows produced $4,422 per acre, whereas the uncovered rows produced $1,100 per acre. In order to economically justify covering raspberries, the cost of the labor and floating row cover must be less than $3,322.
It is worth noting that the raspberries were frozen on September 10 and 11. However, after that time there was not another frost until September 25. If the early frost had not stopped production, yields on both the covered and uncovered raspberries would have been much higher.
Based upon the results in 2007, the covered raspberries produced $4,422 in gross sales. Once harvesting costs of $1,474 are subtracted, the return per acre is $2,948. Then $1,085 is subtracted for floating row cover and the profitability is $1,863.