green manure

[Meow]

i think i'd like to try some green manure on my allotment this year. i've never tried it and dont know a great deal about it. what would you suggest as a good general one to use? i seem to recall reading somewhere that some green manures shouldn't be used before certain crops. any advice, suggestions greatly appreciated. thanks

[Monika]

There is a very recent thread of "green manure" in "Best practices" you may wish to look at!

[Mike Vogel]

There are quite a few threads on this tyopic, Meow. Here is a summary of what I do.

[a] Where i wish to grow brassicas next yera, I sow clover or winter tares. Clover is best not sown now, as it isn't winter hardy, but the tares are nitrogen-fixers, so do the biz.

[b] Where I wish to grow spuds, I sow mustard. This apparently not only cleanses the soil, but, when dug in in the spring, it feeds the wireworm in the soil, which then pupate and turn into click-beetles early enough to fly away before damaging your potato tubers. But that might actually just be a tale.

[c] Phacelia tanacetifolia grows lush and is hardy and I use this where I am going to grow beans.

[d] Hungarian rye grass is also a good bulky green manure to sow, and is also winter hardy. But don't grow it where you intend tro sow things like carrots, because as it decomposes in the soil it inhibits germination. I believe winter tares may do this to some extent as well.

[e] Don't sow mustard where you intend to grow brassicas. Mustard is a brassica itself, and so one aftre the other may encourage clubroot. But it's OK the other way round, and indeed, in rotation you are recommended to grow a green manure of the same family as the previous crop [tares after beans, mustard after brassicas, etc.

Hope this helps.

[valiant veggies]

HI

I have heard comfrey is good, but cant seem to find it in my local garden centers - any suggestions?

[Mike Vogel]

The Organic Catalogue will offer Bocking 14, which flowers but is sterile so is ideal for cutting and making comfrey tea from and helping compost heaps to break down. I dare say any others like T&M or DTBrown will also offer the same variety. But maybe you can beg a root or two from a friendly grower near you.

[John Yeoman]

Forgive me if I've mentioned this before, but spinach is a superb green manure. It's very hardy. You can sow it almost any time of the year, eat it, freeze it or plow it in. Grow a strip of it between rows of vegetables. When you pull the vegetables, replace them with spinach. And rotate those rows of spinach around your plot.

Another option is broad beans - equally hardy. While broad beans don't mulch the soil, their roots add nitrogen. Not quite green manure, of course, but another labour-free way to occupy soil once the more tender plants have been cropped.

[The Mouse]

Another option is broad beans - equally hardy. While broad beans don't mulch the soil, their roots add nitrogen. Not quite green manure, of course, but another labour-free way to occupy soil once the more tender plants have been cropped.

I tried broad beans as a green manure a couple of years ago (having grown my own 'seed' earlier in the year), and was pleased with the results on my heavy soil.

They were sown in September, in fairly sparse rows in order to cover as large an area as possible, and I found that the bed on which they had been grown was very easy to dig in spring compared with beds which had been left bare.
I guess that the roots helped prevent the soil from becoming compacted as it often does in winter with the rain and the weight of any snow that falls. In other words, they helped maintain the soil structure, resulting in a much lighter, more friable soil.

I suppose that many green manures will give similar results, but I just thought I would share my findings regarding broad beans, just in case it is of any help to anyone.

[Mike Vogel]

I have also come across people on the allotments who use sweetcorn as a bulk-ading green manure. They just sow it late and dig it in when it has grown into big plants. It is certainly bulky when it goes into the soil, but I don't know how much good it does compared with other green manures such as grazing rye.

[Johnboy]

Hi Mike,
When people use Maize it may be green in colour but they are using it as a soil improver and not for its fertilizing quality. As such it is best used when it has gone brown and the sap gone out of it. Mind you with Bedfordshire Clay, which is so similar with Hertfordshire Clay, Maize would give very good draining qualities so perhaps they who do use it have cottoned on to a good thing.
JB.

[Mike Vogel]

That could explain things, JB. I'll certainly dig mine straight in this year, as an experiment, rather than putting it on the heap.

[Colin_M]

When people use Maize it may be green in colour but they are using it as a soil improver ...it is best used when it has gone brown and the sap gone out of it.

Can you expand on this JB?

Does it involve digging in the entire plant? With the varieties I grow for edible Maize, the stems are pretty woody by the end of the season. Unless the varieties you have in mind are different, it would seem they'd need some chopping up to stand much chance of decomposing over winter???.

[Nature's Babe]

As long as they are not seeding I think of weeds as green manure, just dry them on the paths then add as a mulch, helps conserve moisture too, the worms work the mulch into the soil

[Johnboy]

Hi Colin,
If you put green maize on the compost you are making compost but to make a soil improver you want to chop it up, or put through a shredder,
and use it in that state immediately or sooner! This means that the material will ultimately decompose in the soil but as it does so it gives your soil an open, better draining texture. It also, because of it's open texture, allows more oxygen to the roots of anything you are growing.
JB.

[Nature's Babe]

Thanks for that suggestion, I will try your chopping method too,, i usually just lay the plants on the soil to protect soil from heavy winter rains and prevent weeds, then in spring I take it up and compost what is left already partly decayed, the worms have eaten some and aerated the soil, it just rots with the rest of the heap, put in compost fresh it doesn't decay as quickly as the rest.

[Johnboy]

Hi NB,
Every year I manure my permanent Bean Bed. Having removed the trellis I
dig out any perennial weeds then spread my manure and allow nature to thoroughly soak the bed then I cover with HD black Polythene until the end of February/begining of March and the worms will have taken the manure in and anything left on the surface is removed, which is never very much. I then give the bed a very light forking over, I don't turn anything in, and then I erect the trellis again and it is ready for planting.
This has worked very well for about 16 years now. It was then that I took Runner Beans out of any rotation. The Bean Bed is in a position where it gets the maximum light the row running north to south and doesn't shade anything. A position like that is very hard to find.
JB.
I appreciate that this is a little off thread.