🌿 Leek

Leeks are best grown in deep, fertile, well-drained soil rich in organic matter (compost is ideal). The root zone should retain moisture but not be waterlogged; avoid heavy, compact or poorly drained soils. Before planting, incorporate well-decomposed compost or aged manure (avoid fresh manure) and maintain regular soil moisture. A slightly acidic to neutral pH is best for leeks (around 6.0-7.0).

Sow in early spring for main crops, or in late winter under cover for an early start. Sow seeds finely to a depth of 1 cm in seed trays/modules or in a seedbed, in fine, firm compost/soil; maintain regular humidity. Germination is optimal at a temperature of around 10-20°C. When seedlings are 15-20 cm high and pencil-thick, transplant to their final location in fertile, well-tended soil in full sun. For traditional blanching, make holes 15 to 20 cm deep with a tiller and plant one seedling per hole, spacing the plants 10 to 15 cm apart and leaving a space of 30 to 45 cm between rows; water and allow the soil to infiltrate naturally (do not fill in the holes). Alternatively, plant in a shallow trench and gradually backfill as the plants grow. Harden indoor plants before planting. Do not weed and water regularly, especially in dry periods. Thin direct seedlings to final spacing.

Leeks are moderately heavy feeders, especially for nitrogen, and perform best in fertile, moisture-holding soil. - Before planting: Incorporate compost or well-decomposed manure and apply a balanced base fertilizer according to soil analysis. In the absence of soil analysis, use a modest, universal fertilizer (equivalent to approximately 50-100 g/m² of a universal granulated feed) incorporated into the topsoil. - Nitrogen management: As leeks grow over a long period, it's best to apply nitrogen in divided doses rather than all at once. Start once plants are established, then side-dress every 3-4 weeks until mid-season (e.g. ammonium calcium nitrate or a high-nitrogen organic source such as blood meal/alfalfa meal/fish feed). Nitrogen applications should be light but regular. - End of season: Reduce or stop high-nitrogen feeding 4 to 6 weeks before harvest to avoid sluggish growth and increased susceptibility to disease. - Potassium and phosphorus: Maintain sufficient P and K for regular growth and good winter hardiness; correct deficiencies according to soil analysis rather than applying excessive amounts. - Containerized leeks: Feed more frequently due to leaching - use a balanced, low-concentration liquid feed every 1-2 weeks once the leek is established. - Practical advice: Water after fertilization; avoid placing powerful fertilizers directly against the stem; maintain soil pH at around 6.0-7.0 for best nutrient availability.

Apply a 2-5 cm mulch of clean straw, leaf mold or well-decomposed compost once leeks are established to conserve moisture and eliminate weeds. Keep mulch slightly back from stems/crowns to reduce rot and slug shelter. Top it up as it decomposes over the course of the season; in hot or dry weather, a thicker layer helps maintain soil moisture at an even level. In cold climates, additional winter mulch can protect plants and reduce soil freezing (remove or thin in spring). Note that mulching does not replace bleaching; if you want longer white stems, use hilling soil around the stems.