The Methane Midden got a ton of press for its attempt to produce energy from brush. And in a suburban backyard no less. But as I spent the day Tuesday finishing its tear down I was struck by the need to set something straight. While the goal of the experiment was to try to produce methane (and hot water in the new Midden), the goal of the system is, and will always be, to make an insane amount of compost. I routinely trailer in over 10 tons of organic matter, mostly woodchips, each year to my .5 acre ( .2 HA) lot and my soils are still far from done. Our urban soils are incredibly denuded in most cases, and until the organic matter content gets up to 5%+ in the top 6″ of soil we have a ton of work to do. And in this region, topsoils used to be 6-10 FEET thick (2-3 m). To add 1″ of compost on even .1 acre you need 13 yards of compost. It is mind numbing to think about how much compost and mulch we need to heal the soil of our cities. Luckily all the carbon we need is unhappily sitting above us in the atmosphere. Hence my desire to cut down coppice and compost it. Putting our tea bags in a bin won’t cut it. The fact that I am working to get energy out of the piles is a fringe benifit. A really, really cool one. 🙂
The break down of the midden was not sexy, but it was awesome none the less – 8 yards of compost, all at once, is simply staggering in what you can do with it. The “compost” was really only about 75% done due to the amount of pine needles, it was really a well cooked mulch – very similar to the “duff” layer in a forest.
Rather than bury you with text I will tell it in pictures. Enjoy:
Cut away of the Finished Methane Midden. The layers of heat exchanger settled over 50%, with the bottom two resting on the ground. Not good - time for a redesign.
What a mess. And you missed all the swearing to get it to this point! Anyone need any yellow garden hose?
Then I started spreading the mulch. The plan was to use the finished compost to start my willow/poplar coppice that I will plant in Spring 2011. It is sized for about 80 trees and will have an understory of Russian Comfrey. Will likely also put in some False Indigo and everbearing raspberries, but I get ahead of myself!
The coppice will be around 3 sides of our kids playground and will have a total row length of about 125' (22 m). This side is close to our fence and is only 2' wide -enough for 1 row of trees..
Good shot of how thick I laid the mulch down here - easily 4-5" (10-12 cm). This is the main width - about 4' (1.5 m) for a double row of willow. Thanks again to author Michael Perry for his help with this during his visit!
The final leg of the coppice to be. Yes, I have 2 wheel barrows... I also have 5 pitchforks - and each has a specific use! So much mulch, and I hadn't even used half the pile yet...
This post may get long, but I really want to pound home the shear amount of Good Work that can be done with one of these Middens – I was beyond giddy driving my barrows around the yard flinging compost at anything that grew! Plus it is a compost eyes view of much of my permaculture beds. I have been asked if I used more energy than I created with the Midden. Yes, I did. But show me an oil rig that can do all this:
'Barrow load under my sole bamboo - a clumper. This will be its first winter -fingers crossed!
Mulch spread in my Asian Pear tree guild - I forked it around the perennials so as to not bury the groundcovers
Wheel barrow load of mulch for my sole apple tree. It speaks volumes that I spread most of this compost "by the wheelbarrow load" rather than the forkful. AWESOME! This still needs to be spread away from the trunk.
- 7-8 barrow loads went on my Sunchoke plantings. Sunchokes are not my favorite food, but this reliably cranks out 50#’s of food for no effort.
Here is the raspberry patch. It was rather overgrown so I hacked it to the ground and refreshed the soil with 8 barrow loads of Midden Mulch. Still not even 75% done with the pile!
Into the Guilds! Mulch under my heirloom Pear - a White Doyne which I have never seen in a catalog, but got from a nurseryman friend.
The other portion of the Pear Tree Guild. This shows one of my Paw Paw's, some hazelnuts, another pear, and a hardy kiwi on the fence. 3-4 more barrows here.
I had so much mulch I decided to start a new guild. This is a pine I bought the year we moved in and is just no starting to grow. In went an elderberry, some thyme, a service berry, and several dozen strawberries. And yes, I just had these lying around...
Mulching under one of my front yard "pretty" guilds, both Peach Tree guilds.
It was so incredibly liberating to be able to spread compost where ever I wanted to – flinging forkfuls into the rain gardens, into the prairie, on the lawn – without have to choose which plants to favor and which had to go without. Also notice that my annual vegetable gardens didn’t get any mulch. This was intentional – this mulch is very carbon intensive at this point, and will be heavily skewed to fungal decomposers which my perennials prefer. The veg garden would have been fine, but the fruiting shrubs and trees would really benefit. Plus I have another 5 yards of compost in my regular bin for the veggies.
The Methane Midden was lined with over 20 bales of straw. These were a wretched mess... perfect for a winter mulch for the veggie gardens!
Now the Methane Midden has passed, but OMG will it live on. I covered everything in this post, plus 3 other guilds, 2 rain gardens, and even some into my mini prairies. Imagine what your gardens will look like if you built 2-3 of these Middens a year? I can’t wait to find out!
Energy is fantastic and very useful up here where it gets to -15 F (-26 C) in the winter, but being able to make this much compost, from invasive species and “weed” trees is where the true beauty is.
Over 8 yards of compost from one pile in the burbs? Epic Shit indeed!
And I can’t wait to do it again – only BIGGER.
Be the Change!