Last September I started off a green manure growing trial, courtesy of the fine folks of SowSeeds.co.uk. As well as their main site they run the rather excellent green manure seed sales and information site GreenManure.co.uk, and they sent me four varieties of autumn-sown green manure crops to try out: caliente mustard, field beans, forage (Hungarian grazing) rye and Italian ryegrass.
I’m sorry to say that I haven’t have much luck with the trial bed that I set up on Plot #59. Of the four batches of seeds sown, only the field beans and a small patch of Italian rye have shown any signs of life.
The sown seeds were covered with fleece for the first few weeks, so I don’t think the rye seeds were pigeon-pecked. Maybe the relatively cool, damp conditions we had in our part of Manchester through September and into October hampered germination, or maybe the seedlings were rasped off by slugs?
Whatever the problem, I don’t really have anything to show for this update. I’ll re-sow once storm Dennis has left us be, and see what happens as the weather (hopefully) warms towards March.
However, I’m much happier to report that we have had more distinct and promising developments on the parallel test we’re running at work, down on the Ordsall Hall and Gardens allotment plot.
The two batches of rye grass both germinated and I think have grown quite well considering the season:

I think the Italian rye is on the left and the Hungarian is on the right (I have to confess I didn’t sow the seed myself, and the records are at work so I’ll have to double-check).
Clearly we’ve had better results from the first grass, the second is a little patchy, so unless it begins to thicken rapidly, I’m anticipating a few annual weed seeds creeping in as well. I’ll monitor the next few weeks’ worth of growth and then it’ll be time to dig in ready for a crop.
Far more distinctly mixed results from the other two seed batches:

The field beans have done reasonably well, with around a 50% – 60% germination rate, and should show stronger signs of growth in the next few weeks. Again though, the caliente mustard seems to have all-but failed. Maybe the heavier clay of Ordsall Hall’s alluvial soil couldn’t retain enough heat to reach germination temperature. Again, we’ll try for a re-sow and see if we can get a result in time for incorporation.
How about you? Have you grown a green manure crop this winter? Do you have a preferred variety, or mix to recommend? Please let me know, via the commments.
2 replies on “2019/20 Green Manure Trial – Winter Update”
Not this year, but on several occasions I have overwintered field beans. I buy 1kg of organic field beans from a wholefood shop for about 80p. I sow two beans per station and thin. We also tend to allow some of the plants to grow to maturity, and eat the beans (I know that’s cheating, i.e. no longer a green manure.
Finally the stems and roots are so significant I have never tried to dig in, simply cut off at ground and plant the next crop in the spaces between the bean stems
That sounds like an excellent method to me, Andrew. I checked on the field bean patch yesterday and a lot of the plants are in flower, so I think I’ll follow your example myself this year and harvest what I can. I like the idea of chopping off at ground level and planting between as well, much more no-dig friendly, and if the beans do re-grow: bonus beans!
Have you tried eating the leafy tops, by the way? I’ve harvested broad bean tops before now and they’re very tasty as a gently-wilted green veg. I’m guessing field bean tops would be similar.