Leek: A Complete Guide To Growing These Forgotten Onions

In many Kenyan kitchens, onions are non-negotiable. Red bulb onions, spring onions, and sometimes shallots dominate the scene. But tucked in the same family is a crop many farmers overlook; the leek.

With its long white stem, mild onion-like taste, and versatility in soups and stews, leeks are slowly carving a niche in urban hotels, restaurants, and high-end groceries. For farmers willing to experiment, this “forgotten onion” could be a hidden income stream.

Why Leeks Make Sense for Kenyan Farmers

• Unlike bulb onions that are prone to price crashes when supply floods the market, leeks enjoy a more stable demand. Hotels and expatriate communities use them frequently, and local households are slowly warming up.
• A kilo of fresh leeks sells between KSh 100–180 in Nairobi and Mombasa markets. Since the crop isn’t yet widely grown, competition is lower, giving early adopters a strong market edge.
• Leeks are hardy, tolerate a wide range of conditions, and store longer in the field than bulb onions, allowing farmers to harvest gradually instead of rushing.

Ideal Climate and Soil

Leeks thrive in cool to moderate climates (15–25°C), making Kenyan highlands and mid-altitude regions ideal. Think Nyeri, Meru, Kericho, Kiambu, Nakuru, and parts of Uasin Gishu.

The crop prefers deep, well-drained loamy soils, rich in organic matter, with a pH of 6–7. Sandy loams are excellent because they allow the white stems to elongate without rotting. Heavy clay soils should be improved with compost and sand.

Land Preparation

Leeks need a fine, well-tilled seedbed. Deep ploughing helps loosen the soil and improve drainage. Apply 8–10 tons of compost or well-rotted manure per acre during land prep. Raised beds (1m wide) are recommended for ease of transplanting, watering, and harvesting.

Since the white stem is the most valuable part, farmers often prepare trenches or shallow ridges that allow soil to be heaped around the stems as the plant grows (blanching).

Seed and Nursery Management

Leeks are grown from seed. A packet of 5–10g seeds costs around KSh 250–600 from Organicfarm or Seedfarm (+254 712 075 915 | info@seedfarm.co.ke), enough for a quarter acre. These certified seeds ensure robust germination and uniform plants for commercial production.

To raise seedlings:

• Prepare a nursery with fine tilth.
• Sow seeds in shallow drills, cover lightly with soil, and water.
• Germination takes 10–14 days.
• Thin seedlings to avoid overcrowding.
• Seedlings are ready for transplanting in 8–10 weeks, when they are pencil-thick and about 15–20cm tall.

Transplanting and Spacing

Transplant into prepared trenches or ridges at 15cm between plants and 30cm between rows. Deeper planting (10–15cm) encourages longer white stems.

Before planting, dip roots in a slurry of compost and water to reduce transplant shock. Water generously after transplanting.

Crop Care and Management

• Watering: Leeks need consistent moisture. Drip irrigation is ideal, but furrow irrigation also works. Avoid waterlogging.
• Weeding: Weed early to prevent competition. Mulching helps suppress weeds and conserve moisture.
• Earthing up (blanching): As leeks grow, heap soil around the stems to keep them white and tender. This is done every 2–3 weeks.
• Fertilization: Top-dress with CAN two weeks after transplanting, then apply NPK or foliar feeds rich in nitrogen and potassium. Organic alternatives like compost teas also work well.

Pests and Diseases

Leeks are generally hardy but can be attacked by:

• Onion thrips: Tiny insects that suck sap, causing silver streaks.
• Cutworms: Attack young seedlings at the base.
• Rust: Shows up as orange spots on leaves.
• Downy mildew: Thrives in damp conditions.

Prevention:

• Rotate crops to reduce disease buildup.
• Avoid overwatering.
• Maintain good field hygiene by removing crop residues.
• Use recommended pesticides when infestations are severe.

Harvesting and Yields

Leeks mature in 3–4 months after transplanting. Harvest when stems are at least 2–3cm thick and 25–30cm long. Farmers can choose to harvest gradually (pulling market-size leeks as needed) or clear the field at once.

Average yields are 10–15 tons per acre under good management. With prices at KSh 100–180 per kilo, the gross returns are attractive compared to many vegetables.

Market Opportunities

Leeks are gaining traction in:

• Urban markets in Nairobi, Kisumu, and Mombasa.
• Hotels and restaurants, especially those serving international cuisine.
• Supermarkets and specialty groceries.
• Direct farm-to-consumer sales, particularly to health-conscious buyers.

Export potential exists to the Middle East and Europe, though this requires strict post-harvest handling.

Challenges to Expect

• Market awareness: Many local consumers are unfamiliar with leeks. Farmers must educate buyers and link up with hotels/restaurants first.
• Labor in blanching: The regular earthing up requires attention, but it’s what makes leeks fetch premium prices.
• Seedling costs and time: Raising seedlings takes longer (up to 10 weeks) compared to crops like sukuma wiki.

Tips for Kenyan Farmers

• Start with a small area (quarter acre) and build market links before scaling up.
• Time planting so that harvesting coincides with dry-season shortages when prices are higher.
• Explore value addition: pre-cleaned, packaged leeks fetch higher prices in supermarkets.
• Combine with other alliums (onions, garlic, chives) for a diversified market offering.