Leeks are another cold season crop we love to plant that is a cousin of the onion and a member of the allium family. The Leeks flavour is in their white stems where it is blanched underground from the sunlight, so therefore Leeks need to be covered or hidden from the sunlight as they grow. Frost tolerant Leeks survive in winter and can be planted into beds in early spring as soon as the ground can be worked. Leeks are extremely hearty plants and virtually pest free and easy to grow. Leeks need both nitrogen and consistant moisture. We prefer starting Leek plugs indoors and after transplanting to our beds, we add a straw mulch to retain moisture around our young seedlings. Unstable watering may leave the stems tough and a continued fertilizing practice every week or so will help stimulate and propagate growth. Soft bellied insects and slugs may attack young plants, so monitoring this is recommended. As far as diseases go, a summer Leek rust may appear especially if there has been a wet growing period, so removing infected leaves should allow a healthy foliage return. Leeks are slow growers, so earlier planting is recommended and can be sown into the ground 8 weeks before the last spring frost date.
As mentioned, other options that we prefer are starting indoors and transplanting the seedlings when they are about the thickness of a pencil. We plant our seedlings approximately 4” wide and deep and spacing the plant 6” apart and 12” between rows and hill the soil around the plants as they grow to blanche the stem.
There are two types of Leeks, early maturing Leeks which are planted in early spring and harvested in mid to late summer which are not cold tolerant. Winter Leeks planted as a seedling for winter harvest, are planted around the first of May, harvesting around mid autumn, and leaving the balance to be harvested from December to mid March. For winter Leeks we will cover them with straw and mini hoop polytunnels or cold frames for these recommended cold tolerant types.
When havesting, carefully loosen the soil with a garden fork at the base of the plant and pull the stock to harvest. There is nothing better than Leek and Potato soup in the cold winter months.