Direct sow in early spring, once soil is workable. 6 seeds per foot, 1/4” deep, rows 24” apart. Thin to 6”. Leeks can also be started inside, in Feb.-March. Days to germination 4-13. Transplant in late spring when plants are about 8-10” tall and pencil thick. Transplant 6” apart in rows spaced 24”, only leaving 2” of leaves above the soil. Use irrigation to fill in soil around the plant, do not compact with hand or tool. For longer blanched stems, hill the soil up around the plants 2-3 times during growing season. Leeks grow best in fertile soil with little weed pressure.
Harvest whole plant anytime, but flavor tends to be best after a few cold nights. If necessary, loosen soil with a garden fork before pulling up plants. Upper leaves can become very tough at full size, but they can still be used for making stock.
Leeks are biennial crops. Dig up pristine roots and store in cool, dry place away from sunlight over the winter. Transplant in early spring at same spacing. Flowering plants may need staking. Harvest seed when capsules split open, revealing black seeds. Minimum population size 5-20 plants. Isolation distance ½ mile.