Green manures

[Primrose]

I see all the seed brochures are starting to advertise their green manure mixtures again and wonder how many of you actually use a green manure during the winter months. I rather like the aesthetic look of a cleanly dug winter vegetable patch and the green manures must make it look very weedy. How much goodness is leached from the soil by leaving it unplanted during winter?

[peter]

The cynic in me always wonders how much goodness is taken out by the growing green manure plants.

[Primrose]

And how much goodness was taken out of my compost heap by the excellent potatoes which grew in it this summer!

[Tony Hague]

I've tried several green manures, with little success. They either fail to emerge, or are outcompeted by the weeds. Perhaps I'm doing it wrong ...?

[FelixLeiter]

The cynic in me always wonders how much goodness is taken out by the growing green manure plants.

Quite a lot of goodness is taken out by the green manure plants. But then it is all put back when the green manure is incorporated, plus sometimes a little bit of extra goodness in the form of nitrogen fixed from the air, in the case of many legumes and certain cereals, plus a good amount of carbon fixed from atmospheric CO2. Their roots improve and preserve soil structure, and the whole plants decompose to add humus, which is retentive and nutritive.

A plot sown with green manures can appear very weedy if indeed there are also weeds growing, which in themselves are no bad thing as long as they are not pernicious. You need to be sure you have a plot which is free of perennial weeds, otherwise you can end up in a right pickle in the spring then it comes to digging it in.

[Monika]

I seem to be a sucker for all these ideas because I have certainly used green manures for quite a few years. I usually use grazing rye which is about 10cm high at the moment (on the beds which grew the potatoes this year). On the ex-pea/broad bean bed I sowed a "winter mixture" (from Moles Seeds) which seems to be mainly mustard and clover. The mustard grew to about 30cm in next to no time, so I cut it back, using the cut stuff in the compost bins, so the clover is now coming through and all that will be dug in in early spring.

My main reason for using green manures is to stop the ground just lying uncovered. The grazing rye usually survives the winter, I don't know about the "winter mixture" yet. I have also used phacelia in the past and usually leave a few plants to flower because the insects love the flower! Field beans were eaten by our mice and voles in the past and even the grazing rye has to be netted because the pheasants eat the seeds and young plants!

[Redfox]

I have one 4mtr x1mtr raised bed with mustard seed in it as the bed was emptied quite early in the season and I didn't want it left empty . I had the seed left over from a previous year so just usedit up. I grew field beans last year but didn't germinate evenly or mice/birds could of got at the seeds/ seedlings
Not sure if it made any difference to the soil as it was quite sporadic and didn't grow very well.
Jane

[hilary]

Hi,
Just be aware of those which are members of the brassica family. All my effort one year was ruined by the pigeons who decimated the mustard crop overnight, leaving me with roots to dig in.

I no longer bother with green manures and spread manure, compost as appropriate and leave as a mulch for the worms to dig in.

Hilary