A DC electromagnet is simply a coil of wire connected to a DC voltage source. It can have an air core or an iron core.
Northern Highbush Varieties. High Chill Varieties. Northern Highbush varieties are the most widely planted blueberries in the world. They grow best in temperate climates where total winter chilling is 1,000 hours or more.Except where listed, most Northern Highbush varieties are relatively self-fertile.orthland is the one of the most cold-hardy Highbush varieties. It is vigorous, easy to grow and adaptable to different soil types and conditions. Northland yields are heavy and the berries are sweet with high sugar content.
Plant Selection There are three basic types of blueberries that will grow in Oklahoma: highbush, rabbiteye, and southern highbush. Highbush blueberries (Vaccinium corymbosum, V. australe) grow 5 to 23 feet tall and require 800 hours of chilling below 45Â° F. They ripen in May, and perform best in northern Oklahoma.