Green Manure crops

[JohnParticipant]

Although I have access to farmyard manure deliveries, I would like to build up a supply of compost from the plot, using the ground vacant before winter brassicas for phacelia and any vacant ground after summer cropping for more phacelia and winter field beans. The idea would be to crop the green manure for the compost heap rather than digging it in. I don’t see much mention of green manure in the method so is this something that is not generally done?

I am coming for the day course on April 1st but there are some jobs I should like to do before then.

Thank you very much.

John

PS I took over my allotment in October. I write an occasional blog for family and friends with several albums of photos including ‘before and after’.
I must admit that I read somewhere that Penelope Hobhouse used Roundup for initial clearance so what ig good enough for Penelope …!

[Don FoleyParticipant]

Hi John,

I can’t see the logic in growing a green manure for the sole purpose of adding it to your compost bin.
One of the main reasons for growing a green manure is to retain nutrients in the soil over winter which will then be returned when the green manure is dug back in. In addition some green manures (legumes) will add additional nitrogen to the soil which the plants extract from the air.
Growing a green manure and then removing it leaves the soil depleted and you will then need to add manure/compost for following crops.
I personally don’t use green manures any more but have had excellent results from them in the past. I now go with Charles’s method of adding a layer of compost/manure which I then cover until I start planting/sowing again in the spring.

Don.

[JohnParticipant]

Hi Don

Thanks for your comments. I did find one entry for Jan 29 15 where Charles had experimented with mustard green manure. He states “I think there will be almost no green on the stems by early March, when I shall rake them off to compost. Then I need to spread this year’s compost”.

My problem is that I have no compost to spread so I would like to ‘grow’ compost to spread later. I also don’t want to dig in the green manures on the no-dig beds. I also plan to grow comfrey as a crop for the compost heap. Ideally I would like to be able to reduce inputs, namely the farmyard manure, that are not generated from within the plot. I am new to the no-dig approach so am I barking up the wrong tree?

John

[Don FoleyParticipant]

Hi John,
You are not barking up the wrong tree as you say but growing a crop purely to create material to add to the compost bin, with the notable exception of Comfrey, is not really practicable. If you need material there are much better ways of accumalating it.
Don.

[charlesModerator]

This is an interesting conversation, good points on both sides. John’s idea can work, I suspect yield will be lower but you can try it. Mustard is ideal for September sowing because of how it dies in frost, though it needs -5C at least. For spring growing I am not sure.
I think its better not to dig them in because when doing that, there is a period of 2-4 weeks when the green matter, stems and roots are breaking down in the soil, and taking nutrients to do so.

[HawfinchParticipant]

What would be wrong with growing the green manure on vacant land and then either letting it freeze down or cutting it at ground level later, leaving the green parts to compost on top of the soil? That is, after all, how many no-till farmers do it, sowing or planting into the ground cover.
Growing a green manure, to me, definitely sounds better than leaving the soil uncovered.

Helle

[bluebellParticipant]

I have been growing phacelia for bees around my fruit bushes, which I remove and compost when the fruit starts to form. Appears to work well in that getting excellent crops due to high levels of pollination, as well as good soil fertility and I have some additional material to compost – so wins all round, although I would hesitate to sow phacelia in an area that I wanted to crop later as I never re-sow after the initial sowing – it just self sets.

[Don FoleyParticipant]

Hi All,

I wouldn’t disagree with anything anyone has posted on this thread.
My point to John was that I thought it impractical to grow a Green Manure purely to generate material to fill the Compost Bin. I absolutely agree with growing Russian Comfrey for this purpose as it is an extremely effective activator.

As far as Green Manures are concerned I have always believed this to be an excellent way to cover bare soil over winter. Green Manure will help retain nutrients from being leached out by winter rain/snow, will add organic matter to the soil when later dug in, will in some cases, i.e., Legumes, add nutrients from the air and those that root deeply will break up lower levels as well as draw up nutrients from these lower levels.
Charles’s point about nitrogen being used to decompose the dug in material is absolutely correct but once the decomposition has been completed I believe this loss is redressed.
Generally you would dig the Green Manure in about 4 weeks prior to sowing a crop so there is no lack of nitrogen for that following crop.

Don.

[JohnParticipant]

Hi All

I am learning to play trumpet and my trumpet forum has distinct ‘schools’ of thought, each based on a different trumpet guru, all quite different but aiming for the same end result. I have discovered that gardening is just the same! There are double diggers, single diggers, no-diggers, green manurers, composters, row planters, block planters, raised bedders, etc!

This discussion has been of great benefit to me. I should like to ask Don to give some detail about ‘if you need material there are much better ways of accumulating it’, bearing in mind that I would like the plot to be as self sufficient as possible, rather than importing lots of material. This is one of the guidelines for ‘best practice’ for organic gardening.

If I had bins full of compost I would not have a problem, but I doubt that the waste just from harvested crops can give sufficient compost to give the annual level of composting that Charles suggests, hence my interest in green manure. Cropping it, rather than digging it in has the dual advantage of bulking up the compost heap and not having the 2-4 week delay before planting following crops.

I will trial it and let you know the results.

John

[peatParticipant]

Don
don’t forget that we are a no dig group. So growing a green manure and adding to compost heap is better than digging it in. Normally green manure is grown on land that is not in use for the time being and would be bare soil which is not what you want.

[Don FoleyParticipant]

Hi Peat,

I fully appreciate that we are a no-dig group but we are talking about digging no more than you would dig to get your Potatoes, leeks, etc out of the ground, or Carrots or Parsnips out of frozen ground.

Don.

[Pete BuddParticipant]

Green Manure has been covered on here in depth before. Charles renamed an extensive thread Green Manure because of the amount of interest but I don`t know how to find it. I started an experiment to grow veg sustainably i.e. no imported fertilisers inc manure to avoid importing pests and/diseases, it worked very well on an allotment I had for 25 years. 5 years ago I took an allotment on a new site which needed a boost to get it going, (I used pig manure). My green manure consists mainly of comfrey, lucerne and grazing rye. Comfrey is a permanent bed, grazing rye is winter cover and I am leaving my beds of lucerne for 2 years at the moment because the subsoil is very compacted and lucerne is very deep rooted. I dont dig my green manure crops in, neither do I dig them out. Comfrey can be used fresh as a nitrogen boost, as an activator or made into a liquid feed. Grazing rye is cut to ground level when fully grown and composted, the roots soon disappear. Lucerne is cropped 2 or 3 times a year and added to compost, when it has to come out I chop it below ground level, (call it digging if you like but its minimal disturbance). Lucerne is very interesting because the roots decompose in the ground and brassicas seem to do well when following it. I could go on but I think thats enough for now.

Cheers

Pete Budd

[StringfellowParticipant]

Here it is Pete, a good one;

http://www.charlesdowding.co.uk/forums/topic/first-early-spuds-green-manures/

Smoothering with a light excluding mulch could also remove a green manure without digging, although the land would be out of use during this period.

Great thread with some interesting ideas.

[Don FoleyParticipant]

Hi John,

I see now where your coming from. I should have read your initial post more closely.
You are trying to build your heap from materials sourced only from your plot?
I’m reasonably certain that you won’t be able to do this at least not on any viable scale.
I can’t see how you would source the required ratio of greens and browns solely from the materials available from your plot.
You will of course accumulate material from the crops you grow but you are also going to need to add other materials such as Cardboard, Newspaper, Autumn Leaves, Grass clippings to name but a few.
“Best Practice” usually carries the proviso “where possible”.

[JohnParticipant]

Hi All

Don
I feel sure that any waste from the plot, as well as minimal amounts of cardboard and veg/fruit peelings from home, will make a compost of sorts, even if it it doesn’t meet the required ratio of greens and browns. Before retiring to a flat without even a window box I had an acre of ornamental garden and, for many years, I ran a grass cutting business and had enormous heaps of grass cuttings which, as you can imagine, were a squelchy mess. However, after leaving them for a few years, I spread the slightly less squelchy mess on the borders in winter and it was surprising how it changed once exposed to the air. I guess this mulch was about 95% grass clippings so I won’t use the word ‘compost’, but it was certainly effective at feeding my soil and garden plants as well as keeping weeds at bay. It must have been manna from heaven for the worms as it soon disappeared into the soil.

Pete
It was great to read Pete’s comments, particularly those in the other thread quoted above. I’ll certainly be trying the annual grazing rye that Pete mentions. I wonder if Pete’s experience is in the UK? My plot is in sunny Exmouth.

John

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