IMG_8270Composting is tremendously rewarding and amazing to witness. I started the mulvey garden back in september 2011 and one of the first things I did was to setup a large composting area. Down the back of the garden was a corner used as a dumping ground for all sorts or organic and inorganic material. After sorting through the layers and removing some material into a skip I eventually got the area cleared. There was a large volume of compost available at the base of the heap which I used to build the garden.
The garden was quite overgrown and the sheer volume of woody material to be removed was too much to be composted within the space so I removed a huge volume of material by bagging it ,loading up the car each week for removal to the in laws place where space for a windrow was available.
I set up a simple 7 bay composting system using pallets and bits of board found in the garden. Each bay has 3 sides and open front. One bay was used for leaves only which are c/n neutral meaning they will break down on their own as they do in a natural system eg. the layers of a forest floor. The other 6 bays were divided in two with separated systems each with an active bay , tossing bay ( for aeration and re heating) and settling bay for maturing the compos. I started chopping up the materials and layering browns carbon rich ( card, paper etc) and greens ( veg , grass clippings) in thin layers 3-4 inches deep. The way to get branches with woody and non woody parts to compost is to strip them down into three piles, leaves, non woody (this years soft growth) and woody . The first too can be added to the compost heap chopped up small and layered the latter chopped up is useful as a mulch on paths. This process take time especially starting out but it pays off when you can harvest half a cubic metre of compost every 6 months.
Starting a fresh compost pile I harvest the mature compost and start by laying a foot deep of woody material ( brash) nothing with a dim of more than 20mm. I then top this off with a few torn up cardboard boxes. The next layer should be a strongly nitrogen rich material, an entire brown bin of grass clippings from the neighbours is perfect. This will put a lot of heat at the heart of the heap. Above this layer will be the best place to put annual wild flowers (weeds) that have gone to seed or if done properly perennial materials. If you were particularly concerned you could put these into a bag for cooking and checking when the pile is turned. Next in might be a layer of stripped leaves mixed with kitchen veg peelings. On this another layer of browns ( card minus the staples, non glossy paper) Repeat the layering untill the bay is over full ( this will quickly slump in a matter of 2 weeks ). It is very import to add moisture to all dry materials as they are layered. I use neat urine with a rose head watering can weekly and since I started doing this the difference in the spread of breakdown has doubled. I turn the pile into the next bay and back 2 or 3 times before harvesting. When harvesting depending on the application intended the compost may need to be sieved and any larger bits thrown back into an active bay.
It’s not possible to produce all the compost required for the garden with a no dig system without either having a completely closed loop system or actively bringing in extra organic materials to offset what one flushes. In an urban setting under rental conditions I have yet to go down the road of the complete close loop system and I,m doubtful that I will or should due to the time frame and environmental responsibilities this requires when I leave.
I,m lucky enough to be living near Eco Logic Organic shop in Dublin and have free access to a large amount of spoiled fruit and veg each week. There is no shortage of Carbon based materials available to mix this with and provide usable volumes of compost. However even with this addition source of materials it’s still not enough to top up all beds by 3 inches or sow each Autumn and spring. This constant feeding is essential for the soils organism as I do not intend digging out the beds and putting manure under soil/compost. Digging out will not allow a soil structure to develop and improve in the long term in my opinion. I like the idea of “Nitrogen draw down” where the enrichment is placed on the surface to break down .
In terms of adding compost below the surface, the standard 4 year rotational system presents an opportunity to do this every 4 years when harvesting potatoes. It’s quite difficult to remove all potatoes without removing the soil first. In some ways this might be seen as a reason to not grow potatoes and perhaps grow Oca instead as a perennial.
Now that the garden is established I have reduced the composting to 3 bays. This has to be one of the most rewarding aspect of gardening turning all that “waste” into usable compost with a wide variety of ingredients. It’s purely a matter of trial and error and being able to decide a course of action for a heap. As a rule of thumb a smelly heap needs some extra carbon rich materials and a dry heap that’s not doing very much needs moisture which is present in Nitrogen rich materials.
All organic materials have both carbon/ nitrogen and other elements .The ideal ration of C/N is 25/30:1 ish. Like the ph scale all materials lie on a spectrum from grass with 9:1 C/N (varies, considered an activator) and cardboard 350:1. In the end you can’t go wrong it all eventually composts, it just the rate that we can influence.At work were organising a visit to Enrich to get some inspiration on tackling the compost heaps. Were also setting up a large leaf mould composting bay using stakes and chicken wire and we were luck enough to have aquired an insulate compost tumbler called a big pig. In theory it should produce compost in 6 weeks but the volume would be about 60 – 80 litres a tiny amount of what is needed. We are also hoping to grow bocking 14 comfrey to harvest as a compost activator into the future.
At the moment I’m reading the Humanure handbook a taboo subject, but one any sensible person should take seriously when designing for the long term.
A great book on composting ” how to make and use compost the ultimate guide ” by Nicky Scott

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