Fig. 3
Strawberries were covered at night when
temperature was below 32° F
Last August, we set up a high tunnel strawberry variety trial at Southwest Purdue Agricultural Center. There are 10 strawberry varieties including 3 dayneutral varieties and 7 June-bearings. Thanks to the nice fall weather, we did have a fall/winter harvest on dayneutral (Albion, Sweet Ann and San Andrea) and two early June-bearing varieties (Sweet Charlie and Radiance). In the winter, we covered the plants with row covers at the nights when temperature was below 32° F (Fig 3), and took the covers off when temperature inside high tunnel was above 60° F. Majority of the cultivars stopped growing in the winter, except ‘Radiance’. We tried to save those ‘Radiance’ flowers growing in the winter, and harvested a few ‘Radiance’ berries in January and February. However, we realize even those flowers survived the low temperatures, it is difficult for them to be completely pollinated.
In late January, we pruned all the dead leaves. This is a very helpful strategy to control pests in the spring. Starting in late February, many new leaves emerged. Plant size almost doubled compared with that in the winter. Currently, almost all the varieties have entered the blooming stage (Fig 4). How to pollinate these flowers while maintaining an idea temperature (50° F – 80° F) inside the high tunnel becomes our biggest challenge at this time. We tried to use a leaf blower to pollinate flowers in early February, but it was not very efficient. We lost some early flowers because of the lack of pollination. Since we started to open the tunnel, pollination improved dramatically. Several green fruit are growing now (Fig. 5). We are looking forward for an early harvest coming very soon. Please watch for our updates in the next issues of Facts for Fancy Fruit.
Fig. 4
Varieties entered flowering stage in early March
Fig. 5 Developing fruit of ‘Sweet Charlie’
(Picture was taken on March 24, 2016).