How to Grow Leeks From Seed

Closely related to onions, leeks grow best in the cool spring season. The thick stems have a mild onion-like flavor that shines when they are added to soups or casseroles. Leeks require a long growing season, so starting them indoors is necessary to ensure they mature before it gets too warm in summer. The roots are easily damaged during transplanting but plantable peat pots prevent root disturbance since the entire pot is transplanted out to the garden bed.

Sowing Seeds

• 1

  Fill compressed peat seedling pots with a soil-less potting mixture. Set the pots inside a shallow pan or tray.

• 2

  Fill the tray with 1 inch of water. Leave the pots to soak up moisture until the surface of the potting mixture becomes moist, then empty the excess moisture from the tray.

• 3

  Sow two seeds per pot, planting them 1/4 inch deep. Cover the pots with a clear sheet of plastic wrap and set the tray in a warm area to germinate.

• 4

  Remove the plastic once sprouts appear, usually within one week of sowing. Move the tray to a warm, sunny window sill.

• 5

  Water the leeks when the soil surface begins to dry. Water at the base of the seedlings until the excess moisture just begins to drip out of the bottom of the pots.

Growing Outside

• 1

  Set the leeks outside in a protected area one week before transplanting, which is approximately four to five weeks before the last expected frost in your area. Gradually move the pots so they are more exposed to sun and wind over the course of the week to acclimatize them to outdoor conditions.

• 2

  Spread 4 inches of compost over the garden bed. Apply 1 lb. of a 16-16-8 analysis fertilizer per 100 square feet and work both the compost and the fertilizer into the top 8 inches of garden soil.

• 3

  Tear the rim off of each peat pot. Plant the leek seedlings so the rim of the pot sits just beneath the soil surface. Space the plants 6 inches apart in rows that are 8 to 16 inches apart.

• 4

  Water the leeks approximately once a week or when the top 1 inch of soil begins to dry. Provide enough moisture at each watering to moisten the top 6 inches of soil in the bed.

• 5

  Fertilize a second time in late May with 1/2 lb. of 21-0-0 analysis fertilizer per every 100 square feet. Apply the fertilizer in between the rows and work it into the top 4 inches of soil.