We are familiar with strawberries grown as a perennial crop in Indiana. Bare root strawberry plants are set in the spring. Fruit is first harvested in the second year and the planting is renovated annually. Using this system, strawberry seasons last for three to four weeks from middle May through June. The
Figure 1. Strawberries grown inside a high tunnel at Southwest Purdue Agricultural Center. Photo was taken on April 16, 2016.
traditional system has been replaced with an annual plasticulture system in the southern United States ever since the 1980s. In the annual plasticulture system, strawberry plugs (rooted runner tips) are transplanted in plastic covered beds in late summer or fall. Fruit are harvested in spring in the next year. After the fruiting season, the plants are removed. The annual plasticulture system is favored in the south because it has a longer harvest period and produces strawberries with better quality. In Indiana, trials established to test the annual plasticulture system had limited success because of short fall season and harsh winter. However, this impression might be changed with the use of high tunnels. Studies have shown that high tunnels extended strawberry season, increased yield and improved berry quality. To test the feasibility of growing strawberries in high tunnels with the annual production system, a trial was conducted at Southwest Purdue Agricultural Center from August 27, 2015 to May 31, 2016 to test yield, quality and harvest period of ten strawberry varieties (Figure 1). In this article, we will discuss the findings of the trial.
Varieties tested in the trial include:
| Albion | Benicia | Camarosa |
| Camino Real | Chandler | Festival |
| Radiance | San Andreas | Sweet Ann |
| Sweet Charlie |
Overall, the trial achieved great success. A total of 1,295 lbs of strawberries were harvested from 660 plants (66 plants of each variety) in a 30 × 96 high tunnel. For most of the varieties, peak harvest season started in middle April and lasted till the end of May. ‘Albion’, ‘San Andreas’ and ‘Sweet Ann’ are day-neutral varieties, they started to produce berries in middle October. But the yield in fall can hardly justify commercial production. The only exception might be ‘Albion’ that produced the most berries in October, November and December (0.17 lb/plant).
The top yielding variety in this trial was Radiance that produced 2.86 lb berries per plant, following by San Andreas (2.37 lb/plant), Chandler (2.17 lb/plant) and Benicia (2.08 lb/plant). ‘Camarosa’, ‘Sweet Ann’ and ‘Sweet Charlie’ had the lowest marketable yield (1.42 lb/plant, 1.62 lb/plant, and 1.69 lb/plant, respectively). ‘Radiance’ produced the most strawberries, it was also the variety that had the longest harvest period. A few ‘Radiance’ strawberry ripened in November, December and during the coldest period in January and February. Primary harvest took off in end April. In the spring, harvest of ‘Sweet Charlie’ and ‘Benicia’ started in early April, about 10 days earlier than other varieties.
We harvested some very large berries; individual berry weight reached 2.7 ounces. Average weight of berries ranged from 0.54 to 0.97 ounces according to varieties. ‘Sweet Ann’ produced the largest berries, followed by ‘Albion’ and ‘Radiance’. ‘Chandler’ and ‘Camarosa’ had the smallest-sized berries. During the peak harvest, ‘Festival’ and ‘Camarosa’ were the sweetest. ‘San Andreas’, ‘Radiance’ and ‘Festival’ had relatively firmer berries while fruit of ‘Chandler’ were much softer, easily being damaged through handling.
| Varieties | Marketable yield (lb/plant) | Average fruit weight (oz.) |
| Albion | 1.70 | 0.87 |
| Benicia | 2.08 | 0.70 |
| Camarosa | 1.42 | 0.56 |
| Camino Real | 1.89 | 0.76 |
| Chandler | 2.17 | 0.54 |
| Festival | 1.88 | 0.72 |
| Radiance | 2.86 | 0.86 |
| San Andreas | 2.37 | 0.72 |
| Sweet Ann | 1.62 | 0.97 |
| Sweet Charlie | 1.69 | 0.59 |
Unmarketable fruit of most of the varieties were less than 15% of the total yield except ‘Sweet Ann’ (21%) and ‘Camarosa’ (18%) in this trial. Most of the unmarketable berries were caused by gray mold. Other disease and pest problems we have encountered include powdery mildew, yellow stripped armyworms and two-spotted spider mites.
Row covers are used for frost protection in the winter. Pollination was carried out by wind.
The 2015/2016 season was featured by warm fall and mild winter that was favorable for strawberry production. In the 2016/2017 season, we will continue to test this strawberry production system with the focus on developing ideal fertility plans.
For more information regarding production practices of the trial, please contact Wenjing Guan at guan40@purdue.edu or (812) 886-0198.
We acknowledge McNitt Growers for donating strawberry plugs for the trial.