SproutSmart
SproutSmart Intelligent Garden Sowing

American Flag

Leek
Botanical illustration of American Flag
🌱 120d to harvest Upright

Sweet, gently oniony flavor with a crisp, tender bite—American Flag leeks form tall, well-filled stalks that feel substantial yet…

Planting Schedule

Add American Flag to your garden to build a schedule and get reminders.

Crop Dates

MilestoneDate
Start IndoorsDec 29th
Last FrostFeb 9th
Transplant / Sow OutdoorsFeb 9th
Harvest BeginsJun 9th
Harvest EndsDec 9th

Crop Details

TraitValue
Days to Maturity120
Sun RequirementsFull SunFull sun
Growth HabitUpright
Support NeededNone
Planting DepthNormal
Germination Temp (°F)55
Min Soil Temp (°F)45
Min Night Temp (°F)30
Harden Off (days)6

Frequently Asked Questions


Why are my American Flag plants developing white, powdery spots on the leaves, and what should I do?
Powdery mildew is common on American Flag as the season warms, showing up as a white, powdery coating on leaves and stems. Remove and discard the worst leaves, then improve airflow by spacing plants and avoiding overhead watering. Spray with a labeled fungicide for powdery mildew (or use an organic option like sulfur or potassium bicarbonate) and reapply according to the product label at 7–10 day intervals until new growth is clean.
How often should I water American Flag during the 60–120 day main growing phase?
During active growth, keep the soil consistently moist but not soggy—aim for about 1 inch of water per week, split into 1–2 waterings depending on heat and soil type. Check moisture 2–3 inches down; water only when it feels dry at that depth. Reduce watering near the end of the season so the roots/plant material doesn’t stay wet while the crop is finishing.
How can I tell when American Flag is ready to harvest at around 120 days?
Harvest when plants reach full size and the tops look mature, with uniform color and firm stems/leaves appropriate for the variety’s typical appearance. If you’re growing for foliage, start harvesting outer portions once leaves are fully expanded and healthy, then continue every few days. If you’re harvesting for a specific edible part that matures over time, begin checking earlier than 120 days and harvest when the intended part is at its firm/mature stage—avoid waiting until foliage looks tired or stays damp.
Botanical illustration of American Flag

Sweet, gently oniony flavor with a crisp, tender bite—American Flag leeks form tall, well-filled stalks that feel substantial yet stay pleasantly delicate. The pale, creamy white to light-green shafts develop with a clean, upright habit, making them ideal for roasting, grilling, and braising, as well as for fresh slicing into salads and slaws. Grow for a bold, garden-to-plate statement: mild enough for everyday use, flavorful enough to shine in sauces and pickling brines.

Sowing Tips

Transplant Conditions

Wait until soil reaches 45°F and nights stay above 30°F before moving outdoors. Harden off for 6 days first.

Expert Note

Because it’s extremely cold-hardy, you can transplant right around last frost for a spring crop or keep it mulched to extend harvest into early spring.