American Leek, a proven garden winner! Leek – American Flag – Allium ampeloprasum Biennial Heirloom. A perfect variety for the home gardener. American Flag has thick blue-green leaves with large white stems,. This variety is good for fall and winter harvesting and will grow quickly from seed. Delicious in soups, stir fries and stews. Soil and Water: Leeks prefer well-drained soil rich in organic matter. Keeping the stems covered with loose soil will keep them bright white. Planting and Growing: Start seeds indoors 6-8 weeks before last frost. Thin seedlings when transplanting and plant 6″ apart about 2 weeks before last frost. Mulch heavily in cold climates. Leeks overwinter well in milder climates. Harvesting and Storage: Use fresh. If heavily mulched over the winter leeks can be harvested as needed. Did You Know? The leek is an ancient national symbol of Wales. In fact, a leek is the cap badge of the Welsh Guards, an infantry division of the British Army. Soil Temperature: 60-80°F Planting Depth: 1/4″ Germination: 5-12 Days Height At Maturity: 15″-20″ Sun/Shade: Full Sun Spacing After Thinning: 6″