Saturday, December 31, 2011

Making compost in 18 days with Geoff Lawton

Building up layers of different materials

cold composting bins
We cold compost, which is to say that we add material to our compost piles as it arrives from kitchen or vegetable plot and it moulders away, decomposing slowly.  We alternately use four adjacent boxes and when the compost is about ready, we empty that box and riddle it to remove uncomposted material, which goes back into a fresher pile.  It takes months to make compost this way but is relatively low maintenance.

if you just add water at the end, it won't soak through evenly
The alternative is hot composting, which involves creating a large pile all at once (which heats up) and then turning it regularly to maintain the heat.  We've tried it before but were inspired to have another go after watching the very specific advice from permaculture hero Geoff Lawton, on his new video, Permaculture Soils 

His informing belief is that “it’s not the soil itself, it’s the soil life that is the most important element.”  He teaches us to inoculate the soil with bacteria by using a very diverse mixture of compostable materials such as different manures (the nitrogen component) dried grass toppings, green grass clippings (providing the ‘yeasts’) along with shredded and partially rotted wood (food for fungi). 

six days in
He talks about adding activators, such as urine, comfrey, nettles, yarrow, fish or animal remains to kick start the decomposition process.  He also mentions adding charcoal for its surface area (I’ll blog about what I’ve recently learnt of biochar soon). The whole lot should be wetted (see below).  One needs enough material to create a minimum of one cubic metre in total, otherwise it won’t get up to the necessary temperature. 
Cat enjoying the warmth generated by the compost process

We gathered pig manure, chicken droppings, rabbit pellets and sheep poo.  We added wheat straw and fresh grass clippings, chipped wood and comfrey leaves and litres of wee collected from our urine-separating compost toilet.

He talks of having 25 parts nitrogen to 1 part carbon but, as I wrote in my recent article for PermacultureMagazine on our compost toilet: “The ideal carbon/nitrogen ratio of 30 : 1 is often quoted but rarely explained.  It certainly doesn’t mean 30 times as much straw as solids; in fact, both faeces and urine contain carbon and nitrogen in their chemical makeup…  Don’t bother getting the scales and tape measure out as you search for the correct amount.”  It’s a learning process and you’ll find that too much nitrogen means that the pile gets too hot and reduces in volume, losing goodness to oxidation.  Too little and your pile won’t get warm enough to kill weed seeds and break down the woody material.
8 days and the colour is beginning to change

There are two criteria to measure, that’s the moisture content and the temperature.  For the first, grab a handful and squeeze: it should just drip.  For the temperature, he tells us to shove our hand in.  TAKE CARE, as it can get really hot.  Be sensible and open up the pile a bit and get a feel before you actually touch it.  At 60ºC, you wouldn’t be able to leave your hand there.  We actually used a meat thermometer and pushed the whole thing in, probe, dial and all, leaving it for a few minutes before retrieving it and looking at the temperature.  We tried it in several positions in the pile.  Aim for a min of 50ºC max 70ºC, ideally between 55 and 65.  (Above 70ºC is beyond the limit of life for our decomposing bacteria and the process becomes anaerobic.) 
10 days

Construct your pile, cover it up with old tarps or plastic sheeting (leaving an air gap at the bottom) and leave for four days.  Then unwrap and turn the pile.  We used a pitchfork and rebuilt the pile alongside itself, trying to put the stuff that was on the outside on the inside and vice-versa (if you see what I mean!)  Wrap the rebuilt pile up again and, from then on, the pile gets turned every two days for the next fortnight, reaching its maximum temperature on the second or third turn, i.e., 6 or 8 days into the process, when it should attain the ideal of around 60ºC.  Geoff’s claim is that, if you get it right, it gets hot enough and decomposes without losing volume.
16 days and the heat has reduced but we're seeing fungal growth

The photo sequence shows our experiences with our first two batches.  We now think that the moisture content is vital and ended up adding a lot at the start to pass the squeeze test and a bit during the turning process.  We think we had proportionally too little nitrogen on the first batch, maintaining volume but not being fully composted at the end and never quite getting up to the desired temperature.  We overdid the nitrogen in the second version, getting good decomposition but losing a lot of volume.

This last photo shows our second attempt, at the end of the process.  It's much darker, has decomposed more than the first but we've lost volume.  

We can generate or get access to the necessary amount of material to build a cubic metre pile and it’s very useful to create such a quantity of compost in just 18 days or so, so we will keep trying.


Cally said...

This is a fabulous post. I love composting and always love to have more insights and ideas. I'll definitely be trying out a few more techniques in my repertoire now so thank you.

I was wondering if you might add your smallholding to Folia the online gardening website (it's free). I'm always looking to encourage more gardeners to join and am having an extra push this week while the weather is keeping most people indoors.

It's a great resource for gardeners and has helped me keep on top of my 800+ plantings with photo's, notes, journals, milestones etc. They have an extensive plant wiki and a seed stash section where people can also list seeds for swapping. Here's the link to my Folia page so you can see how it works:

Stuart and Gabrielle said...

Hi Cally,

Thanks for stopping by our blog and leaving a comment. When I clicked on the link to look at your pages on Folia, it wanted me to sign up first. It looks interesting but I already spend too much time on the computer for the moment and quite enjoy my paper notes and plans for the garden. So, I'll decline for the moment but might have a look at it again in the future.

Cally said...

Thanks for letting me know that happened, turns out it only goes direct to my page from my own computer because I'm signed in but my friend said he tested it at work and that there is a little bit on the sign-up page that says CDfolia and if you click that it goes to my pages. Bit annoying but at least now I now what it's doing.

I'm a big fan of having things on paper too, I like to sit in bed in the wee small hours making plans and wishlists. I think what I liked most about Folia was the ability to add a new plant to it's wiki and then have that linked to the notes page so that I could put everything from all my multitude of notes into one spot, and include web links (to seed sites, recipes, people blogging about that plant etc.).

But you are right, it's all time on the computer. I tend to neglect it through Summer and use it much more in the colder months. I was so glad about is recently when the Winter Gales ripped nearly all the labels from my plantings. Now I have a rough idea of what and where the new plants and seeds are - if the winds haven't removed them too!

I was so engrossed in your compost article that I didn't notice your holiday cottage photo until my next visit, I'll be bookmarking that into my 'hopefully-one-day-I'll-get-a-holiday' folder.

I haven't been to Brittany since I was 8 and would love to visit again, If ever I can find someone trustworthy to watch my garden for me. The only green fingered friend I have is someone who would come on the holiday too.

Stuart and Gabrielle said...

Hi Cally,
I think it was simply the link you gave me: (i.e., without the /invite bit) goes straight to your page.

I've just come in for a quick lunch ("Palestine artichoke" by Jane Grigson) before carrying on with our cob and stone barn conversion, so I'll have a longer look at your folia site later.

It would be lovely to welcome you here. Later this year, and certainly by next year, we'll have the second small gite for hire, so more places to stay and the ideal way to holiday with friends (they don't have to share one's space!)

best wishes,