Turnips provide a dual crop for the gardener because both the roots and the greens make a delicious meal. Sow turnip green seeds in the early spring to harvest an early summer crop or in the late summer to harvest a late autumn crop. When you plant turnip green seeds to harvest the greens only, the time to maturity is shorter than if you wish to harvest the turnip roots.
Prepare the growing area as early as possible in the spring or in the late summer when the temperatures begin to cool slightly. Cultivate the soil with the garden spade down to a depth of at least 6 inches. Add 2 inches of compost to the top of the soil and work the compost in with the garden spade. Rake the soil and compost smooth to finish preparing the growing area.
Make a ½-inch deep planting hole every 10 inches. Make the rows 1 to 2 feet apart. Place 3 turnip green seeds in each hole and cover them with ½-inch of soil.
Water the newly planted turnip green seeds generously immediately after planting. Keep the soil evenly moist while the seeds germinate and while the seedlings are establishing in the soil.
Thin the turnip green seedlings when they are 2 inches high. Remove the weakest seedlings so the seedlings are 6 inches apart. Thin the seedlings again when they are 4 inches high, removing the weakest plants so the seedlings are between 2 and 4 inches apart. Reserve the greens and prepare them in the kitchen if they are big enough.
Harvest turnip greens when the plants are approximately 6 inches high. Keep the roots in the soil and they will continue to produce greens. Harvest the greens every ten days until the roots stop producing.