Friday, 15 March 2013

Digging in green manures

The lads make short work of the field beans!
In Blackhill this Autumn we did several trials on sowing green manures (including sowing summer varieties under cloches for winter). In all we did four beds, one with cloched mustard and phacelia, one with field beans, one with grazing rye and the final bed was split between lupins and a green manure mixed packet that included vetch and rye. We came back to the beds recently to record the results before digging in the whole lot.Eileen plans to use these beds for first early potatoes so we dug them in early to get them to break down and release their food in time for the spuds.

digging in the mixed green manure Annmarie, Sylvia, Sharon & Sue

Under the cloche the Phacelia and mustard did surprisingly well despite some of the freezing overnight temperatures we had in January and February. The growth was abundant and strong with the mustard in particular being very prolific and healthy. In the same bed unprotected phacelia had germinated erratically and was much poorer so the usefulness of the cloche is not to be sneezed at-particularly in winter.

By complete contrast the grazing rye was a complete no show-nothing at all to suggest we had even sown it in the first place! This happens to me all the time, personally I think my slugs eat it, so I have long given up any hope of using it in the garden. It's a pity really as grazing rye is supposed to be the very best soil improver for heavy clay-except it won't grow on my heavy clay! (there is a truckload of irony in there somewhere).

Greg, Kay and Kathleen digging in the phacelia and mustard

The lupins didn't germinate at all, they just rotted away on the surface of the soil. The green manure mix was a bit hit and miss, vetch and some type of other legume that looked like a pea were doing well, the rye in the mix was sporadic at best, complicated by annual grasses growing through it at the same time and it was hard to tell what else might be a green manure. But the coverage was pretty decent, so no complaints there.

The best by far were the field beans, they almost all germinated well, grew a little and were short fat plants when we dug them in. I don't know about the rest of you but these are my favourite winter green manures, you can bet the farm on them they are so reliable. If you never try any other winter green manure give these seeds a go.
field beans under cover being tended to by Pat at Cappamore

So what next? now we wait, depending on the weather it should take a few weeks for the stems, roots and leaves of the green manures to break down in the soil. If you are digging in your own green manure be sure to flip the root upwards and chop it up really well. Actually chop up everything as well as you can to help it all to break down quickly. Lobbing up the root is essential particularly with field beans as the plant will start to regrow if you just chop off the leaves and leave the root intact.


  1. Thanks for the manure tips, I shall have to put them into action!

  2. Hope they are useful for you!

  3. Hi, We planted green manures but the 'digging in' part was hard work, I thought sowing them would be easier!
    No such problems this year as we have had to move to a new allotment site, on virgin ground.
    Nothing actually in the ground as yet due to the cold weather.

  4. Hey Peggy!
    Its not an easy job on your own. Yesterday a group of 6 dug in a fine high crop of field beans in a tunnel bed for class and it was a pleasure to see how they made short work of it.

    I'm looking forward to your posts on your new site. I hope that we are out of our cold spell now and headed for a long hot summer where we complain to anyone who will listen how we are sick of watering and are being mistaken for continentals with our tans!! Out with the child of prague in anticipation!!!