Container Production of Southern Highbush Blueberries Using High Tunnels

Blueberry production in Mississippi (MS) is mainly rabbiteye blueberries (Vaccinium virgatum Ait.), which ripen in late May to June. Growing early-ripening southern highbush blueberries (SHBs) (Vaccinium corymbosum L.) presents an opportunity for early fruit production and increased market price for locally produced blueberries, yet faces the challenge of spring frost damage. One-year-old liners of 10 SHB cultivars were transplanted into 15-gallon plastic containers and placed in a high tunnel in Apr. 2015. Blueberry plants were fertilized with either a conventional or an organic fertilizer at comparable rates. Plants were evaluated for berry yield, timing of first berry harvest and peak harvest, single berry weight, and soluble solid content during the 2016 and 2017 growing seasons. The high tunnel increased monthly maximum temperature by 3.2 to 10.4 degrees C, monthly average temperature by 0.7 to 4.2 degrees C, and minimum monthly temperature for up to 3.0 degrees C compared with outdoor environment. Photosynthetically active radiation (PAR) at noon in the high tunnel ranged from 477 to 1411 mu mol.mL(-2).s(-1) and relative humidity ranged from 54.6% to 81.7% from Jan. 2016 to June 2017. SHBs in the high tunnel produced first berry harvest during the first week of April in both growing seasons. Total berry yield per plant ranged from 921 g to 2136 g in 2016 and from 1222 g to 2480 g in 2017. Compared with the organic fertilizer, conventional fertilizer increased berry yield in April and May, and total berry yield in 2016, but resulted in similar yield in 2017. Eight cultivars (Emerald, Farthing, Gupton, Meadowlark, Pearl, Rebel, Star, and Sweetcrisp) produced single berries that averaged more than 2 g per berry in 2016, compared with two cultivars (Gupton and Pearl) in 2017. Smaller berry size may have resulted from the generally increasing yield from 2016 to 2017. 'Sweetcrisp' produced berries with higher soluble solid content, 14.2% and 14.1% in 2016 and 2017, than the other nine cultivars. Container production of SHB cultivars in a high tunnel produced total berry yield equivalent to 6458 kg/ha in 2016 to 7500 kg/ha in 2017, advanced blueberry production by 4 to 5 weeks, and therefore may serve as a potential production system for early fruiting blueberries in Mississippi.