Leek AUTUMN GIANT/HANNIBAL 400 SEEDS £1.70 Quantity: at £1.70 each Add To Basket Matures from October but can stand right through winter. Has dark green leaves and thick heavy stems. Leeks grow best in a deep, fertile soil. Sowing instructions: Sow from February in rows 40 cm apart and thin later to 15 cm. Or raise plants in a seedbed and plant out in June at 40x15 cm. Growing instructions: Ridge up a few times when the plants are growing. Average contents: 400 seeds.