|'Shogoin' has greens ready for eating after about 30 days, and a root after about 55 days. Mature roots are 3 to 4 inches across, with white skin and a flat top. The greens are 18 inches high, and have a mild taste. The greens are especially recommended. The turnip is a bienneal that is grown as an annual. This temperate climate crop grows best when temperatures are around 68 degrees F. Soil should be moist, but well drained and have a medium to low fertility level.
Turnips tend to bolt when soil becomes dry. Once ground is workable in spring, sow seeds and continue doing so about every 3 weeks until the first of summer or until weather gets too hot at about 3/4 inch deep. Space rows 9 inches apart and thin plants with scissors so they are about 4 inches apart. Early turnips can be harvested at about 5 weeks and main crop anywhere from 6 to 10 weeks. Much later than that and plants will be too tough.