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How to Plant Leeks

By M.H. Dyer ; Updated September 21, 2017

If you've never planted leeks in your garden, give them a try and you won't be disappointed. Leeks are a sweeter, milder version of their cousin, the onion. Although leeks may seem like a gourmet food, they are hardy and very adaptable to the home garden and are especially delicious in meat dishes, casseroles and soup. Plant leek seeds directly in the soil, or get an early start by planting the seeds indoors.

Plant leek seeds indoors in late February or March. In eight to 10 weeks, the leeks will be big enough to be transplanted into the garden.

Fill a divided planting tray with commercial potting mixture. You can also plant leek seeds in small peat pots. Peat pots are convenient because they can be easily planted in the soil pot and all, as the pot will soon decompose.

Water the commercial potting mixture well before planting the leek seeds. The potting mixture will settle, so add more potting mixture to bring the level up so that the planting container is nearly full.

Plant the leek seeds 1/2 inch deep in the commercial potting mixture, leaving at least 1/4 inch between seeds.

Place the planting container under a grow light with only 2 to 4 inches between the seedlings and the light. Leave the light on for 12 to 14 hours each day, but turn it off at night because the seedlings need a dark period to develop correctly. An electric heating mat is beneficial if you have one. Otherwise, keep the containers in a warm room away from drafts.

Keep the potting mixture moist but don't water excessively. A spray bottle works well, as it won't disturb the leek seeds.

Prepare the leek seedlings to be transplanted outdoors when there is no danger of frost in your area, and the daytime temperatures have warmed to about 45 degrees F. Harden the seedlings off for about a week so they won't be shocked by the sudden change in environment. The first day, put them outdoors for about an hour. Add an hour every day until the seedlings are accustomed to being outdoors, then move them to their permanent place in your garden.

Work the garden soil in preparation for the leek seedlings. Incorporate 1 to 2 lbs. of general purpose granular fertilizer and 5 to 6 inches of compost or well-rotted manure into the top 8 inches of the soil. Cultivate the soil well and remove any rocks.

Remove the leek seedlings carefully from the planting container, and plant the seedlings in the soil 5 to 6 inches apart. The leeks will be better if they're planted deeply, with just a few inches of leaf showing. If you're planting the leeks in rows, leave at least 20 inches in the rows to allow space for weeding and hoeing. Water the leeks deeply once every week.

Begin harvesting leeks for use in the kitchen when the stalks are 1/2 to 1 inch in diameter. If you live in a cool climate with hard freezes, harvest the leeks for use before the ground freezes. If you live in a warmer climate with light freezes, overwinter leeks by covering them with a mound of garden soil, followed by a thick layer of organic mulch such as straw or bark chips.


Things You Will Need

  • Leek seeds
  • Divided planting tray or small peat pots
  • Grow light
  • Electric heating mat (optional)
  • General purpose granular fertilizer
  • Compost or well-rotted manure
  • Organ mulch for overwintering


  • Leek seeds can be planted directly into prepared garden soil about a month before the last frost in your area. Plant the leek seeds about 1/2 inch deep in prepared soil, with an inch between each seed. If you're planting the seeds in rows, leave about 20 inches between rows.

About the Author


M.H. Dyer began her writing career as a staff writer at a community newspaper and is now a full-time commercial writer. She writes about a variety of topics, with a focus on sustainable, pesticide- and herbicide-free gardening. She is an Oregon State University Master Gardener and Master Naturalist and holds a Master of Fine Arts in creative nonfiction writing.