In previous years, in my clay-heavy soil, I have grown reasonable leeks. They have, however, been somewhat short and stumpy without the long blanched stems that you’d hope for. This season, using a no-dig approach, I’ve managed to grow much longer leeks with whiter stems.
For those that are new to my “Diaries of a Rocket Gardener”, I have switched to no-dig, which basically means that rather than digging over the soil each autumn/spring, I simply cover it with a thick layer of organic mulch, usually a mixture of compost and well rotted manure. If you’ve not come across it before, I’d definitely recommend investigating this approach as it is proving very beneficial – Charles Dowding’s website is a good place to start.
So, the raised bed where I planted my leeks had a good 7cm thick layer of compost over the top of the soil. I dubbed (or dabbed?) a hole when planting them and watered them in as I normally do. Of course, the compost is that much looser than the clay soil underneath, and I think this really helped them. Even with the soil being well-dug in previous years it was always very heavy and clumpy leaving the leeks little room beneath the soil’s surface to grow, so most of the growth was exposed to sunlight, thus the greener stems. This season, they were able to grow under the soil much more easily, and have been so much more successful as a result.