Green Manure - Mulching, producing biomas, living mulch

Hello all,

I'm a Brit living in France and am part of a large permaculture community garden. We have a decent surface area, though not enough mulch is produced onsite so we occasionally buy in the odd bail of straw, or the city council leaves us the odd pile of wood chips. The problem is that it's never enough to cover all the plots, so I've been looking at other solutions and have started to experiment with green manures as a potential solution. I've watched lots of videos on youtube and recently invested in a book dedicated to explaining the practice, but I wanted to see if some members of the community had first hand experience using them to produce a decent quantity of mulch for the garden.

I've planted rye and mustard so far. The mustard planted in August grew really well and has just taken a hit with the frost but it looks like it will provide a decent blanket for the soil over the winter. The rye is only about 10 cm max for the moment, I think I should have planted earlier in the season to produce a better amount of biomass. I planted it at the end of September/early October. I don't intend to work the green manures into the soil.

What's your advice on the type of green manure to use for producing lots of external biomass?

I've also read about the possibility of keeping a permanent layer of 'living mulch' in the form of green manures and planting in to them. In theory this would eliminate or reduce the need to mulch with externally brought in material and provide good soil structure and permanent ground cover. The idea would be to 'chop and drop' every so often to give light to the crops planted and reduce competition for nutrients. Potential problems that spring to mind are slugs and difficulty sowing seed directly.

Has anyone had any experience with planting in plots where green manures are established and used as a living mulch?

Cheers,

Jimbo

I've noticed that when I do a living mulch layer of clover mixes I get tons of slugs, and so now if I'm doing a cover crop of clover for rows it will be to produce green mulch and I'll chop it down completely. My best luck has been intensive planting to reduce weed pressure as I find it's pretty laborious to go through and "mow" down the cover crop between all the plants I have within. Alfalfa is a good one to produce a good amount of high-energy biomass that is a big hit with soil microbes as it breaks down. Wheat and rye are top of the list to my knowledge for biomass per foot, and after drying store easily.

A natural farming technique for soil restoration and producing biomass is to plant corn, let it grow to about 3 feet, then chop it and chip it before turning it into the soil or mulching with it. The corn seed has contains enough energy to grow to that size without eating up much in the way of soil nutrients, and its stems can contain high amounts of K. Sunflowers might work very similarly. Food for thought!

Jimbo Delboy wrote:

What's your advice on the type of green manure to use for producing lots of external biomass?


Jimbo

Oh, and of course comfrey if you have the space for it, is a fantastic biomass producer and said biomass is incredibly rich in nutrients. Also, it can be a trap crop for your slugs if you’re experiencing part of them. Obviously it may not be the choice for interplanting, but I have a few beds where I planted sterile comfrey on one or both ends, then the green manure is right where I need it and the surrounding soil benefits from work activity around the comfrey. Happy gardening!

Thanks Aaron.

We've got a patch dedicated to comfrey for making teas and having an extra a bit of mulch. It's not subtstantial enough to produce lots of biomass but it helps nonetheless.

I think I'll try planting more densely this year and I'll check out Alfalfa, too.

I like to rub comfrey leaves between my hands to break it up a bit and put some in a hole with a transplant, brings some worms and beneficial microbes right to the root zone of the seedling.

Keep in mind plants heights and growing patterns when interplanting, it will help you from overcrowding while still maximizing harvest and keeping the soil photosynthesizing.

Hello Jimbo, where are you? Can you post some pictures so we get an idea of the place?
I'm in France too. If you're in the city, i'd go for approaching green minded gardener companies, they love to get rid of their wood chips.
And probably have friends that do too.

But growing some green manures is awesome too..

I've got a creeping comfrey that does very well and reproduces like crazy. A bit too good for some situations maybe.
My reye is only small, just managed to get my hands on some good seeds that grow here in the area last month.
I'm doing Dutch white clover as well.