My success with onions last year made me want to add leeks to the allium lineup. Leeks require a longer investment in garden space, anywhere from 6 to 14 months in the garden. The advice for growing them in my mild winter climate is to sow seeds indoors in December or January or outdoors in January through March. Mature leeks should be ready for harvesting sometime in September. One of the advantages of growing leeks is that they can stay in the garden through the winter so harvesting can continue until about mid-March when they should start to bloom. The problem with that long time frame in the garden is that they can hog some serious space for a long time. But, there is a technique that can minimize the space that they hog for part of their time in the garden - growing in a seedbed and then transplanting the young plants to their final spot in the garden.
My foray into growing leeks started back on December 17 when I sowed seeds for Blue Solaise and Lungo della Riviera leeks into 4-inch pots, one pot for each variety. On February 14 I set the seedlings out in the garden, two rows of tiny little seedlings spaced about 1-inch apart. It's a bit difficult to see below, but they are the wispy little things at the top of the photo (almost invisible, not the seedlings with white bases), the rest of the seedlings in the bed are onions. Everything is covered with netting because the birds will pluck at anything green at that time of the year.
Ideally, the leek seedlings should be lifted and and set into their final positions when they get to be the size of a pencil, but some of mine got to be a bit bigger, more like the diameter of my forefinger.
|Leeks in their seedbed on May 9|
|Leeks on the right, onions on the left|
|Leeks sorted by size|
Using the seedbed method allowed me to grow a crop of cabbages in the space where the leeks might have been planted had I chosen to set them out at their ultimate spacing back in February. I used my usual amendments of compost, crab meal, sulfate of potash, and Azomite, plus an extra dose of nitrogen in the form of blood meal. I dug a small trench about 7 inches deep, sprinkled in some Mykos mycorrhizal fungi inoculant and placed the leeks four inches apart with their roots in the center of the trench.
I partially filled in the trench and then nudged the leeks into an upright position and finished filling in the trench. I used Azos bacterial inoculant when I watered them in. Planting deep like this also eliminates a chore that would be required if I had set them into their final positions as little tiny transplants. The best part of a leek is the white portion of the shaft and the shaft will not turn white unless it is blanched. The traditional method of blanching is to hill soil up around the leeks as they grow or to start the leeks in trenches and add soil as they grow. Either way, you need to have a mound of soil sitting somewhere for hilling or filling and I don't have a convenient space for that. Transplanting larger leeks into a trench and filling it in may be more work at the time you have to do it, but in the long run it saves time and space.
I ended up with three rows of leeks, about 22 leeks per row, each row 9 inches apart. I'm not sure if they are too close together, the recommendation is to set them out 4 to 6 inches apart and I chose the closer spacing.
The smallest of the seedlings went into the space where they spent the last three months, the plan being to harvest them first as babies. When the onions are ready to pull then the space will have to be cleared to make way for fall and overwintering vegetables.
The only issue that I've had with the leeks so far is that they have been infected with rust - Puccinia porri. Rust in alliums is extremely difficult to control. There are no recommended organic treatments but I seem to be having some success with a 70% extract of Neem oil. It doesn't cure the problem but it does seem to slow it down. About 2 tablespoons of Neem extract per gallon of water sprayed about twice a week to start has been very helpful. The biggest problem with Neem extract is that it has a distinct aroma and flavor so it gives an off flavor to anything that it is sprayed on. I'm hoping that the rust infection will largely disappear when the weather gets warmer and drier, but even so, the parts of the leeks that aren't treated, the shafts, will be fine to eat.