Leeks are a cool weather crop and can be started early in the season.
They are a cousin to the green onion but grow much larger and have a mellow flavour.
How To Grow Leeks
Starting Seeds Indoors
Being a cool weather crop you can start them early indoors to get a head start on the season. Plan to start leeks 4 – 6 weeks before your last frost date.
To start leeks sow seeds 1/4 inch deep in the planting cells. If you have florescent lights place the seed tray under the lights for the best growth. If you do not have lights, place the seeded tray in a warm sunny location, be sure to keep the soil moist, if you have a lid for the tray it is a good idea to use it until the seeds have germinated. Once the seeds are sprouted remove the lid and keep the tray in a warm sunny spot.
Germination should start within 10 – 15 days.
Once plants are 6 inches tall you can begin to introduce them to the outdoors by hardening off the plants. They can be moved into the garden after all chances of a hard frost have passed.
How Do I Harden Off Plants for The Outdoors
Hardening off plants is important for the transition from the controlled environment indoors to the wild outdoors. Most plants that are started indoors will die if exposed to the harsh outdoor elements for more than a few hours. With hardening off over a period of time, plants are exposed longer and longer to the sun and wind so they can get strong enough to be outdoors.
Harden off plants for a week or two before moving into the garden by setting them outdoors for a few hours every day. The goal is to gradually leave them out for longer periods until they are strong enough to withstand the elements.
Be sure to protect them from harsh wind and direct sunlight for most of week one. Toward the end of the week, you can start to expose the plants to full sun for a few hours a day. Depending on nighttime temperatures you can leave them outside overnight during the second week.
Where Should I Plant Leeks
Leeks do not do well in container gardening so inground gardens or deep beds are best suited for growing leeks.
Leeks prefer sunshine so choose a spot that receives full sun for up to 8 hours. Dig the soil well adding amendments like peat moss and compost. If your soil is hard and compact the addition of sand helps to loosen the soil and aides with drainage.
Transplant leeks when they are 4 – 6 inches tall. Space the plants 6 – 8 inches apart with rows being at least 12 inches apart. Make nice deep skinny holes to place the transplants in. A long screw driver works or even the handle end of a rake works well, just stick straight downwards into the soil and move in a circular motion to create a hole.
Place the transplant into the hole and gently pat the soil around the stem. You do not have to back fill the hole, that will happen naturally when watered or from the rain. You can bury part of the transplant under the soil line for stability.
The Trenching Method of Planting Leeks
Alternately you can go with the trenching method to plant the leeks. With the trenching method you are creating an 8 inch deep trench the length of the entire row. The leek seedlings are then laid in the trench spaced 6 – 8 inches apart with the green part pointing upwards.
Using a hoe works best for the next part. We want to gently pull the soil upwards over the roots and partially up the stem. Water well and add a light layer of mulch. As the plant row continue to mulch the leeks or use soil to cover the growing stems.
How To Care For Leeks
Mulch your plants well if that is a practice you implement in the garden. Because the white part of the leek is the most desirable part of the leek, plants are hilled like potatoes to blanche the stems, this keeps the stems covered and hidden from the sun so they stay white. This prevents chlorophyll from developing in the covered part of the stems. If you do not use mulch in the garden, cover the stems of the leeks with dirt, like you are hilling a potato plant.
Be sure to water well, leeks should not be allowed to dry out. As their root system is shallow mulching is a great option to keep the plants roots wet. Grass cuttings works very well as mulch.
If you have ever seen white asparagus, it is because the plant was grown in trenches and covered as it was growing to prevent it from turning green.
When Should I Harvest Leeks
You can start harvesting leeks when the white part of the stem is around 1 inch thick and 3 inches long. Unlike onions, the tops of the leeks do not die back to signal they are ready for harvest.
Most varieties can take anywhere from 90 to 120 days to mature. As they are a cool weather crop they can remain in the ground until the first frost and can handle temperatures as cold a -5C.
Use a pitchfork or shovel to dig out the leeks. If you have nice loose soil or are growing in a bed, give the leek a slight twist and remove from the soil. Place the shovel or fork into the soil 6 inches away from the plant, gently loosen the soil while lifting the leek out of the ground.
Brush off as much soil as possible then rinse well. Because leeks are enjoyed best fresh, only harvest what you need.
How Do I Store Leeks
To store leeks, they can be wrapped in damp paper towel and stored in the crisper drawer. You can trim the greens down for fit but keep the roots on until they are to be used.
You can use leeks in numerous ways, be sure to wash them well before using. The way that leeks are grown causes them to trap dirt between the layers.
For long term storage leeks can also be chopped and frozen for use during the winter months. After the leeks are clean, slice the stem lengthwise down the center. Now slice the stems into half-moons. Place on a parchment lined baking sheet and place in the freezer. Once the leeks are frozen, they can be bagged up in freezer bags or vacuum sealed.
Leeks can also be dehydrated. Slice the leeks quite fine and place in the dehydrator at 145F until they are completely dry. Store in a covered jar in the pantry.