Diversity leads to resilience:
This is one of my stock answers to a lot of problems in an organic kitchen garden. It applies to so much, and there is no change when it comes to composting. If one approach fails, then a contingency plan is well worth having.
This spring at River Cottage, we’re mainly composting in three ways: a thermophilic bay system, a wormery, and a bioreactor. Each different approach has its benefits and drawbacks.
Bays are quickest - taking as little as four weeks - and can deal with large amounts of garden waste. We’re grateful for that in the busy spring clearance of our overwintered cover crops. However, they also need routine and preparation, with the waste being chopped up into smaller pieces before being added. We turn ours into the next bay every one to two weeks. The wormery provides beautiful, fine, nutrient rich compost, but can take longer to get going and can’t take large amounts of waste at the same time. The bioreactor makes a fungally dominated, carbon rich compost, ideal to mimic the abundance of a forest floor, albeit in 12-18 months time and requiring all the materials to be assembled the same day..
What goes onto our growing areas is a mixture of all three, giving the widest possible selection of microorganisms a chance to improve our soil.
Don’t listen to advice...
A strange thing to say when sharing tips, I know. However, there’s a lot of advice out there. Thousands of blogs and books and videos telling you exactly how to do it and how not to do it, which can be intimidating and put people off even beginning to try something new.
Different things will work for different people. Some will say you should have a 3:1 ratio of brown and green waste measured by weight, but what should you do when the next article says it should be 2:2:1 with carbon rich, nitrogen rich, and a ‘biological activator’ measured by volume? No wonder people give up and go to the garden centre.
The truth is that there is no right way, that every site is different, and that every gardener is different. It’s about finding the kernels of truth in the advice and working out why a method works, before adapting it to your own site and work habits. In our bays, we use roughly half and half green (nitrogen rich) and brown (carbon rich) materials, built in layers over the course of a few weeks. When the bay is full, it is turned into the next bay. But don’t blindly follow that either! Leading nicely to…
Find what works for you:
Whatever you do, it’s rare that you’ll have incredible success the first time around. Since I first started at River Cottage, the garden team has tried all sorts of ways of composting. We had huge bays - 6 feet square and 5 feet deep - and never had the time to turn them. We made a series of stacking sugi-ban frames which made for easier turning, but took ages to build and could only make one batch at a time. We tried collecting huge amounts of materials in exacting ratios and built a pile in a single day, mixing the green and brown ingredients fresh and monitoring it closely. It composted well, but we had nowhere to put the next day’s garden waste while it did so. The worm bin fell out of repair at busy times of the year, or was overfilled and attracted flies.
Every trial lead me to think that simple, routine based practices worked best. None of it can work in a day, but a little bit of thought a couple of times a week accumulates to a working system. Now, our bays are simple - three 4ft pallets tied together with wire; quick to build, easy to replace, and can be turned by one person in half an hour. We cut up our garden waste as we collect it, and add it to the first of 4 bays, adding more green or brown materials to maintain a good mix when we need to.
There are no failures, only lessons...
Learning from the mistakes of the last tip, it’s good to accept that any practice will change and improve over time. The way we’re currently composting won't stay the same forever, and expecting 100% success will only lead to disappointment.
There are still batches which don’t break down as we’d like them to, or don’t get hot enough to kill off whatever weed seeds have found their way in. One batch full of couch grass might just do a good job filling in a trench made by a tractor wheel. Sometimes you don’t get compost in the timescale you want, just a rough top dressing to mulch a fruit bush or tree with, which is what I did when we moved some gooseberries last autumn.
The compost we make has improved, not because we went back to the drawing board and tried a new technique, but because we persevered with our existing approach, tweaked what was already working and dropped what wasn’t.
I find that with anything, diving right in and enjoying the process works as much better motivation than dreaming of (and putting pressure on) an outcome with specific criteria for success.
With compost, I love that we have soil thermometers to see what is happening inside the heap every day. I make it part of my morning routine to record it in a spreadsheet, which plots a graph of that pile’s temperature. That monitoring makes the process one that is part of my gardening day, and part of the ecological cycle rather than alienating the composting tasks from the growing tasks.
I hear microscopy can be a kick too, but feel like I could get lost down that rabbit hole if I’m not careful.
Whilst we make as much of our own garden compost as possible onsite at HQ – with the scale at which we are working to and the inclusion of new landscaping projects, large scale bed renovations and compost for propagation – it simply isn’t possible for us to consistently produce the amount we need. One of the reasons for this is feasibility, with a small team and a dozen other priorities.
Another is the need for specialist seed and cutting compost, which is finer and freer draining than a standard compost and can make a huge difference to germination rates and health of young plants. Naturally, River Cottage wouldn’t use unsustainable peat-based composts. I think we should aim for better than importing coir from the tropics, too. So, with this in mind, we’ve recently been on the search for a sustainable solution and have partnered up with RocketGro, who create composts using digestate from biogas production in our neighbouring Somerset. Their seed and cutting mix has given us brilliant results this year, and is fully organic certified as well!