Leek American Flag

Climate

• Leeks are a cool season crop and grow best in temperate climates.
• They can tolerate light frosts, making them suitable for most regions in Australia.

Soil Preparation

pH:

• Leeks prefer well-draining, fertile soil with a pH between 6.0 and 7.0.

Choose a Sunny Spot:

• Leeks need at least 6 hours of sunlight per day.

Improve Soil Structure:

• Add organic matter such as compost or well-rotted manure to improve soil fertility and drainage.

Loosen the Soil:

• Leeks grow long roots, so loosen the soil to a depth of at least 30 cm.

Fertilise:

• Incorporate a balanced organic fertiliser or slow-release fertiliser into the soil before planting.

Planting Leeks

 How to Plant

Sowing Seeds:

• Start seeds indoors 8–10 weeks before the last frost date or sow directly into the garden. See zone guide in product description.
• Sow seeds 5 mm deep and 15 cm apart.

Transplanting Seedlings:

• When seedlings are pencil thick, transplant them into the garden.
• Dig a trench to cover root ball and space seedlings 15cm apart.
• Place seedlings into the trench and cover the roots with soil, leaving the top part of the plant exposed.
• As the leeks grow, gradually fill in the trench to blanch the stems (this keeps them tender and white).

Care and Maintenance

Watering:

• Keep the soil consistently moist but not waterlogged. Leeks need about 2.5 cm of water per week.
• Mulch around the plants to retain moisture and suppress weeds.

Fertilising:

• Side dress with a nitrogen rich fertiliser every 4–6 weeks to promote healthy growth.

Weeding:

• Keep the area weed free to reduce competition for nutrients and water.

Pests and Diseases:

• Watch for onion thrips, aphids, and leek moths.
• Use insecticidal soap or neem oil if necessary.

Diseases:

• Leeks can be affected by rust, downy mildew, and white rot.
• Practice crop rotation and avoid overwatering to prevent these issues.

Harvesting

When to Harvest:

• Harvest leeks when they reach about 2–3 cm in diameter.
• Younger leeks are more tender, while older ones have a stronger flavour.

How to Harvest:

• Gently loosen the soil around the leek with a fork and pull it out.
• Trim the roots and leaves if needed.

Companion Planting for Leeks

Good Companions

Carrots:

• Leeks repel carrot flies, while carrots deter leek moths.

Celery:

• Both plants have similar soil and water requirements.

Onions and Garlic:

• These Alliums share similar growing conditions and can help deter pests.

Lettuce and Spinach:

• These leafy greens grow quickly and provide ground cover, reducing weeds.

Tomatoes:

• Leeks can help deter aphids from tomato plants.

Herbs (e.g., thyme, rosemary, and sage):

• These herbs repel pests and improve flavour.

Plants to Avoid

Beans and Peas:

• These legumes can inhibit the growth of leeks.

Asparagus:

• Leeks can stunt the growth of asparagus.

Tips for Success

Blanching:

• To produce long, white stems, hill soil around the base of the leeks as they grow.

Succession Planting:

• Sow seeds every 3–4 weeks for a continuous harvest.

Crop Rotation:

• Avoid planting leeks or other Alliums in the same spot for at least 3 years to prevent soilborne diseases.