It’s been just over a year that I completed Elaine Ingham’s Life in the Soil classes. It seems a good time to take stock, as we go into the colder part of the year when practical fieldwork winds down. So what have I learned?
There is certainly promise in the end results – very visibly in the case of the beans, and noticeably in the improved taste and productivity of the tomatoes. We only have one polytunnel for the tomatoes in 2016, but we got almost as much yield this year from this one than from two polytunnels of tomatoes [ref]We have three polytunnels, all of the same size and colocated[/ref] in 2015.
I know of no way of quantitatively analysing taste, but several of our CSA members observed the much better flavour of our tomatoes compared with shop bought ones. However, one other thing we changed across the years was have a dedicated CSA member Ann look after the tomatoes, pinching out all the offshoots and training the stems along the frames. Because we could not afford a control plot with the tomatoes, the almost doubling of yield could be the result of her extra care and attention to detail, or a combination of the her work assisted by the compost extract.
The compost extract was used in the polytunnel with the tomatoes in July 2015 and some of what was left over was also used in polytunnel 1 which was where the beans were planted, with the ribbon tied to the frame to show the extent of the coverage, the left behind compost after extraction also went into the tomatoes in polytunnel 2.
Not every attempt showed success – last year we tried some outdoor tests on defined plots in the sweetcorn crop. This crop was lost to the initially wet and dull start to 2015 and not enough manpower for weeding. I felt there was some difference in one of the plots, but not enough to make a clear picture and not enough to redeem the crop.
I do have the suspicion that compost extract takes time to work its magic – the tomatoes and beans that showed the results clearest to me were both crops from 2016, whereas this photo was taken in early September 2015, and the compost extract was only made in mid-July that year. It’s possible that in compost extract concentrations it only acts as an inoculation, and the microorganisms need more than nearly two months to breed enough. The 2016 crops had had a full life cycle of soil life and the soil life had more time to breed before they started.
Technical and process knowledge gained.
The Esmée Fairbairn Foundation funded some of this work in 2015 and their support is gratefully acknowledged.
I started the Elaine Ingham Life in the Soil Class course in 2015, completing with the final Microscope Class[ref]Unlike some online courses you did have to get enough questions right to pass ;)[/ref] in September 2015
I don’t have any growing or horticultural background, Joanne was the obvious person to do the course but running the Oak Tree Farm takes up more than 100% of her time particularly last year with the crowdfunding, but this looked like a very interesting opportunity that squares with the ethos of the farm so we ran with it. So I was coming from a standing start and lacking domain knowledge, although of course Joanne and other members of the farm were there to help.
Joanne’s note: Richard is being modest here. He has a scientific background which has been invaluable in getting rigour into the whole process, and he has also set up and mastered our second hand microscope complete with low cost camera and projection system which is a huge help when we look at the soil/compost samples together.
What I learned was:
Matching the Elaine Ingham temperature profile is difficult
Getting the heap over 55C for three periods of three days[ref]the specification is more complicated than that – hold above 55C for three days, or above 65 for two days, and take action earlier at higher temperatures[/ref] is difficult, if you look at the progress we have had several failures to reach this for one period, never mind three, but we are inching our way towards getting this more repeatable, and haven’t had any total wipeouts this year. On the upside, we have had success, and the failures tended to fail safe, drying out rather than going anaerobic, generating bad smells and producing anaerobic organisms in the compost.
We can only successfully make compost on a small scale
To scale up we would need larger scale machinery. We have had greatest success with a large garden-sized plastic compost bin, and none with the open-weave ‘hardware cloth’ netting. We adopted the latter to slightly upscale, but we struggle for material and manpower, because we have no mechanical assistance. As a result we’ve chosen to focus on the more enclosed plastic bin, to minimise the variables and match the task to our resources better. As a result
Ambient temperature matters
We did not appreciate this in the beginning, and some to the composting videos in the life in the Soil Class show people doing this in the balmy climate of Southern California around 38°N rather than on a windswept site in East Anglia at a latitude of 51°N. You can make compost in wintry temperatures and some of Elaine’s compost video shows industrial compost production in windrows while there’s snow on the ground, but that is better on a big scale where the surface area to volume ratio is smaller, losing less heat, proportionally.
We need to shelter our compost much more from the wind – I established it near a hedgerow at a lower part of the field but there is more work to do here. This is of course correlated with the smaller scale at the moment.
This influence of the ambient limits our capacity to make compost to roughly when ambient[ref]the wind affects us too, it is not just temperature[/ref] is more than 10-15C in the daytime. I will establish a standing temperature monitoring station nearby with a basic louvred screen[ref]this minimises the effect of direct sun giving false high readings, see Met Office Fact Sheet 17, Observations over land[/ref] to give a control reference on future temperature logs.
Controlling the composition matters but it is hard
I have tried to avoid the use of manures in the compost making for several reasons. One is that it stinks, but more importantly it is very variable, and of course as the product of an anaerobic decomposition process it contains anaerobic microbes and pathogens, which makes matching the temperature profile much more important. Doing that right effectively pasteurises the compost, in Ingham’s course it appears that the anaerobic pathogens are more sensitive to heat than the good[ref]good for our purposes of aerobic decomposition[/ref] aerobic microbes, which can go dormant as long as the rate of change is not too fast. I have taken the line that without manure, if we screw up on the temperature profile the worst result is we won’t have killed off all the weed seeds.
The high N part of the compost heap is the smallest proportion by volume, as a result variations in this impact the mix disproportionately. Getting this from plant material is tough and always occurs together with green material, as a result you have to make some estimate of the mix and take that into account. Although it’s only arithmetic this is not something that is easy to do in the field. I started to improve my results when I started to write this down and state my assumptions on the mix.
Better rigour and improved record-keeping is good
I have every admiration for people who can build good compost heaps using experience and know-how. I found better records helped me build on experience and be able to look back and integrate results, both good and bad. Which is the material that kicked this website off.
Conclusion
It works, but it’s not easy and there’s a lot more to learn.