Mid-Atlantic citrus growers’ greenhouses learning to stretch out season
Lemon and lime trees are bathing in the outdoor sunlight for a slightly extended season, thanks to October’s temperate 70-degree days.
The Mid-Atlantic is outside of Hardiness Zones 9 to 11 that the USDA considers most favorable for growing citrus trees and other tropical varieties said to survive to around freezing or 28 degrees, and so nurseries and garden centers such as Homestead Gardens purchase from Florida.
Temperatures have, however, warmed enough over the centuries that small portions of Maryland and Virginia are now designated Zone 8a, near enough the desired growing zones that they lend themselves to growing tropicals, Albert Ayeni of Rutgers’ plant biologydepartment, said.
The National Oceanic and Atmospheric Administration’s Wakefield, Va., office shows that an average of 76.4 degrees Fahrenheit in September 1875 increased to an average 80 degrees F in 2020. As temperatures rise and habitats shift due to human-caused climate change, planting zones are shifting north, according to the independent non-profit Climate Central.
Rutgers has so far discovered that plants from as far as India and Nigeria grow well in New Jersey: exotic peppers, tropical spinach, okra, sesame, Egusi melons, cocoyam, tigernuts, fluted pumpkin, Indian Jute, African, Chinese and Indian eggplants and Asian cucurbits are among them, Ayeni said.
Ayeni works as an ethnic crop research specialist leader at Rutgers. He also serves as coordinator for the Rutgers’ Entrepreneurship Ag Program and the university’s Internships in Production and Entrepreneurship Ag.
The plants, he said, maintain the same observable traits when grown in New Jersey as they do when cultivated in the tropics and subtropics, but soil conditions and agronomic practices may cause some size and performance differences.
Dan Ward, an assistant Extension specialist in pomology at the Rutgers Agricultural Research and Extension Center, said weather fluctuations — the late frost that this past May followed a warm early spring, for instance — can be more challenging than the temperature ranges within different zones.
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