Phacelia: pherny and phlowery. Or it would be if I hadn’t just cut it down yesterday. Sown in September, now left to wilt and melt into the soil, it’s going to provide a lovely green manure for my drying beans, making them extra nutritious and successful.
Phacelia is a nitrogen-fixing legume. Nodules on the roots are the site of a symbiotic relationship between plant and soil micro organisms. These take nitrogen from the air and turn it into a form the plant can absorb. Nitrogen is a macronutrient for plants, responsible for full verdant leafage and proteins – proteins for essential cellular processes as well as storage in seeds. The seeds I want to eat are beans!!
So, I’ve cut down the phacelia and the nodule nitrate is ready to fertilise my crop. In addition, the bulk of the leaves also adds nitrogen, as well as organic matter that aids good soil structure, which in turn facilitates the microflora, which aid the fertility of the soil…see feed the earth, link to Incredible Edible Lambeth blog.
Green manure is a bit of a luxury for urban growers: every precious square foot wants a crop. I had the opportunity to sow phacelia in last year’s blighted tomato patch. The patch was vacant sooner than expected and it conditions were still more than warm enough for germination. The plants over-wintered well, protecting the soil from battering rain which washes out nutrients and ruins aforesaid soil sturcture. My feeling, too, was that sowing the green manure had a remediating effect after my blight trauma, though I know of no reason why green manure would destroy spores fallen into the soil.
More thoughts – organic growing and permaculture angles
Organic best practice (indeed farming since Anglo-saxon times, if GCSE memory serves me right) encourages a fallow replenishment of the soil on rotation using green manure. But Garden Organic’s guidelines have an agricultural history, which extends to large allotment growing, and is just beginning, in my experience, to encompass the reality of many people wanting to grow their own in restricted space. Green manure is not easy to incorporate into a growing plan. Hungarian rye and clover: this is for fields!
Permaculture wants all bare ground covered to maintain soil structure and the fauna within it: immediately you remove a crop, have another transplant ready or a handful of green manure seed ready. I find this a useful principle but in practice I’m not always ready with a seedling to pop in. I’ve used buckwheat as a quick green manure. I particularly like for its hover fly attracting properties and the tricorn seeds which are lovely to fiddle with. However, it then overshadows the crop I’ve eventually managed to sow. Still, it can just be turned in, the stems all crunchy – it’s good at mining calcium, apparently.