The majority of strawberry growers in New Hampshire cultivate "June-bearing" varieties. This plant-type requires cool temperatures and a decrease in day-length (as we see in autumn and winter) to stimulate growth for the following year's fruit. This physiological need limits strawberry production in the Northeast to a brief 4 to 6 week period each year, and prevents area growers from participating heavily in the region's commercial strawberry market beyond that of that traditional "strawberry season" despite very strong consumer demand for fresh and locally produced berries.
However, a different strawberry fruiting type exists that does not require an environmental change to stimulate fruit production. These varieties are called "day-neutrals" and are widely cultivated throughout high producing regions of the US, such as California and Florida, and are also very popular in areas with strong direct-market sales, such as North Carolina. Yields of 20,000 lbs/acre are commonly seen with day-neutrals, and yields of 27,000 lbs/acre (1.8 lbs per plant) have also been recorded in the Northeast. These fruit yield figures are a HUGE increase over the 5,900 lbs/acre New Hampshire growers reported in a 2012 census by the USDA National Agricultural Statistics Service.
When day-neutral varieties are coupled with a plastic mulching system, the plants produce higher yields, larger fruit and will begin fruiting within 10 weeks of planting, not the following year as June-bearers do. Coupling day-neutral varieties with plastic mulch alone has many benefits, but the addition of low-tunnels (already utilized by many growers in the Northeast for season-extension) can magnify these benefits and extend the production season to nearly 6-months in the Northeast.
These portable structures allow growers more control over the environment around their plants and studies show their inclusion results in even greater yields, higher plant survival rates, and larger average berry size than to uncovered/open-field production. Low-tunnels are particularly useful in Northeast where hail, heavy rains, strong wind, and other inclement weather is common during the summer growing season, putting growers at a competitive disadvantage over other regions of the country when it comes to consistently supplying fresh berries.
Despite mounting interest and availability from local nurseries, these varieties have not been widely adopted by New Hampshire growers. In this trial we will use one tried-and-true day-neutral variety ('Albion') in a plasticulture system with low-tunnels. Our primary objective is to evaluate this system for New Hampshire growers and determine the most suitable materials for the extension of strawberry season using day-neutral varieties.
This project is supported by the New Hampshire Agricultural Experiment Station and Tunnel Berries, a USDA National Institute of Food and Agriculture Specialty Crops Research Initiative grant titled "Optimizing Protected Culture for Berry Crops" in collaboration with the following universities: