Leeks are a perennial, but are commonly treated as an annual. They have a long growing season (75 to 150 days). Leeks are in the onion family, but you may find that it has a sweeter flavor than the average onion. They are commonly used in soups and sauces.
- Fast Growers: King Richard, Columbus, and Varna (75 to 80 days to maturity)
- Slow Growers: Titan, and Giant Musselburgh (sweeter and milder; 105 to 150 days to maturity)
When to Plant
You can start your leeks indoors in mid winter. When they grow to about 6 to 8 inches tall, cut them back to about 2 inches. In early spring, you will then plant them outdoors. You can also start your plants outside in the spring from seed. Choose a sunny location for your leeks.
Spacing and Depth
To transplant your seedlings outside, separate the plants and plant them about six inches apart. When planting seeds, prepare a shallow trench and thinly sow the seeds. Cover the seeds with a just a small layer of soil. Immediately water with a light shower so as not to disturb the seeds.
As the leeks grow, you will want to bank up the soil around them. If you choose to bank with mulch instead, you will need to pack it tightly. Banking keeps the leeks from turning green.
You can harvest the leeks when they are as small as a pencil, but are considered better when they are larger and more mature. Since the leeks can be left outside through the winter and into spring, they are best harvested right before use. Use a fork to loosen the soil around the leek and then pull them up by the leaves.