Leeks are members of the Allium family that do not form bulbs like their onion and garlic relatives. Instead, they develop a 6 to 10-inch edible stem that can be up to 3 inches in diameter.
Planting
- Transplant seedlings in August to September.
- Plant baby leeks 1 to 2 inches apart, mid-size leeks 4 to 8 inches apart, and full size 8 to 10 inches apart
- For long blanched shanks, plant seedlings in a hole up to the first leaf.
- For additional blanched length, plant seedlings at the bottom of a V-shaped trench. Fill in the trench and hill soil up around the stems as they grow.
- Cardboard tubes from toilet paper or paper towels can be placed over the growing seedlings for additional stem blanching.
- If growing your own transplants, start the seeds 10 to 12 weeks before you want to plant.
- Leek seedlings are relatively easy to separate, so transplants can be grown densely in pots.
Harvesting
Large leeks generally require 100 to 120 days to mature. Harvest at desired size: ½ to 1 inches in diameter for baby leeks, 1 to 2 inches for mid-size, or 2 to 3 inches for full size.
Pest management
Leeks are subject to similar pests and diseases as Onions and Garlic, UC IPM.
More links
Growing Onions & Leeks, Center for Agroecology and Sustainable Food Systems (CASFS), UC Santa Cruz
Recommended varieties for Santa Clara County*
| Carentan, OP | Long, thick leek grows strong and vigorously, with a delicate and delicious flavor. Up to 2 inches across. An old European heirloom variety. 18 to 24 inches tall. Plant 4 to 6 inches apart |
* Many other varieties may also do well here in Santa Clara County. This list is based on UC Master Gardener trials, taste tests, and feedback from local growers.