In praise of leeks
By Dawn Pettinelli - UConn Home & Garden Education Center
Featured Article - posted Tue., Mar. 5, 2013
Sitting here savoring the last of a delicious batch of potato leek soup, I am thinking that it is about time to start some seeds for this year’s crop of leeks. Known for their subtle onion flavor, leeks were prized by the Pharaohs and the Romans as well as by today’s food connoisseurs. In fact, they are said to be among the earliest cultivated vegetables.
Although they do require a long growing season, with some varieties taking up to 140 days to mature, I find them one of the easiest and most rewarding vegetables to grow. There are a number of fine choices to grow. I have always had good luck with King Richard (75 days) and Lancelot (95 days), but other promising selections include Megaton F1 (90 days), Giant Musselburgh (105 days), Blue Solaise (105 days) and Tadorna (100 days). Consider growing both early and late varieties for an extended harvest.
Leeks require a sunny, well-drained site. They do best in a deep, fertile soil enriched with organic matter. Add limestone, if necessary, to raise the pH up to about 6.5.
Because of their long growing season, leeks are best started indoors sometime from late January through early March. Any sterile seedling starting mix will do. I usually start mine in flats, planting the seeds about a quarter of an inch deep. Germination takes about seven to 14 days at 70 degrees F. When the grass-like seedlings are 2 inches high, either thin them to an inch apart or transplant them into cell packs or individual 2-inch pots.
I have seen it advised to trim the tops of the young plants when they get 3 or 4 inches tall, but I really didn’t notice that much of a difference in growth when I did give them a haircut. As soon as the plants reach about 6 inches or so and the weather starts to settle, begin hardening off your plants to prepare them for the move to the garden.
Leeks are generally set in 4- to 6-inch deep trenches, depending on the size of the transplants. By trenching the leeks, the bottom stalk is blanched, producing a larger portion of succulent, white stem. Set plants 4 to 6 inches apart in rows 8 to 12 inches wide. As the seedlings grow, you can begin to fill in the trenches with an inch of soil every three weeks or so. The idea is to blanch, not bury them.
If you are just growing a few plants, you can set them into a 6-inch dibble hole leaving the top 1 to 2 inches of the plant above the soil. Leave the soil relatively loose around the stems so that irrigation or rain water can gently settle the soil. Some gardeners prefer to slip 6-inch cardboard tubes over the leeks instead of growing them in trenches. I have not tried this, so I can’t say how well this works.
In all the years I have grown leeks, never have I seen any insect pest devouring them or any sign of disease. Leeks are truly trouble-free plants. They do need to be kept weed-free, as they start growing rather slowly and can be easily overshadowed by more vigorous weed species.
Like most vegetables, leeks do best if they receive about an inch of water every week. Follow soil test recommendations when applying fertilizer. Since leeks are long season plants, they may need to be sidedressed mid-summer at half the recommended fertilizer rate.
Nice, fat stalks should develop by late summer. If you can resist the temptation, leeks should be left in the ground until hit by a frost or two. The cool weather causes their starches to be converted into sugars, resulting in a tastier harvest. However, they can be consumed at any stage of growth.
Harvest by trimming the leaves and digging or pulling up the whole stalk. Trim the roots and wash the soil from them. The leeks can then be stored in the vegetable crisper in the refrigerator for several weeks.
If you have questions about growing leeks or on other indoor or outdoor gardening topics, call the UConn Home & Garden Education Center, toll-free, at 877-486-6271, visit the website at www.ladybug.uconn.edu or contact your local Cooperative Extension Center.