Florida strawberries are grown as annuals started from northern-sourced cold-treated young plants set out in September and October. Bare-root plants with their leaves retained yield earlier than plants with leaves removed. However, frequent irrigation (8-14 hours/day for the first 10-15 days) to cool the leaves and keep them moist until the roots can start growing can lead to increased disease and leaching of nutrients out of the root zone. In addition, our warm fall temperatures may cause excessive runnering and plant growth at the cost of flower initiation and fruit yield. Newer cultivars are less sensitive to heat, but the old standards are most accepted by customers.
UF/IFAS researchers wanted to test earlier planting in the hotter months with a technique to keep the plants cooler and reduce water use. Kaolin clay is often used to reduce heat stress in plants. A spray application of this white clay leaves a residue on the leaves that reflects the heat back and keeps the plants cooler but can reduce photosynthesis. They tested 10 days of sprinkler irrigation to keep the plants cool, 10 days of irrigation followed by kaolin clay application, 7 days of sprinkler irrigation, and 7 days of sprinkler irrigation followed by kaolin clay application. They also tested planting date with plants planted mid-September, late September, and early October using the above four irrigation practices. ‘Florida Radiance’ and Sweet Sensation® ‘Florida 127’ were the cultivars tested over three consecutive seasons in west-central Florida.
Results and Conclusions
Early planting in mid-September with ‘Florida 127’, a cultivar bred for more heat resistance, resulted in a 25% increase in early yield compared with an early October planting date, although total yields were no different. ‘Florida 127’ had a greater total yield than ‘Florida Radiance’. Both cultivars had greater early yield, but no different total yield, with the earlier planting date.
Water use can be reduced, and early yields increased 19% from the traditional strawberry establishment treatment of 10 days of irrigation by using a 7-day irrigation followed by application of kaolin clay.
Dates and Transplant Establishment Methods on Early-yield Strawberry in West-central Florida. By E.A. Torres-Quezada, L. Zotarelli, V.M. Whitaker, R.L. Darnell, B.M. Santos, and K.T. Morgan. HortTechnology. October 2018 28(5):615-623.