We are using 160901 to make compost tea. Although the temperature has fallen to ambient, it’s still a bit early. This is only seven weeks old, and it’s apparent that while all the green material and plant material has gone and isn’t recognisable for what it is, the woodchip takes longer to break down. As such it will be mainly bacterial, the fungi take longer to develop. Fungi are better at decomposing woody material. But sometimes it is not worth letting the perfect be the enemy of the good.
compost 160901 after seven weeks
Looking back at the success we had with the beans there is some latency of a few months between putting the compost organisms out, compared with the more modest results after only a couple of months, so we want to get this out now to do its work over the winter. Continue reading “Making compost tea”
Compost extract was a great success but it seems to take time to take effect. The effect on the sweetcorn was marginally noticeable with only a month and a half, whereas the beans were very noticeable the next year.
If this hypothesis is true (other differences are the crops were different, and the beans and tomatoes were in the polytunnels and the sweetcorn outside) then we need to really get the compost extract out now for next year.
Close-up of 160901 compost
The 160901 compost isn’t really ready, although it has fallen back to ambient temperature, so we chose to run the experiment to get ahead. This is much more bacterial than fungal under the microscope, which is to be expected as bacterial reproduction is so much faster. But needs must in this case.
We adopted a tip from Nigel of Landews Meadow Farm in Kent and trialled using about 0.5kg of compost stirred vigorously into about 40l of water in a trug. This is more economical with the compost than the method we used last year, so we can make more extract from a given amount of compost if it works, and it is more suited to our volumes for experimentation distributing by hand. The other method is more suited to bigger volumes and mechanical spraying, because the net curtain filter screens the particle size so it is less likely to clog pumps and nozzles.
The aim is to stir fast enough to establish a vortex in the water and occasionally reverse direction. Shades of Steiner’s biodynamics here, but also a good way to aerate a volume of water by hand.
Ben, visiting from Frith Farm CSA in Hull gave us a hand with stirring the extract
Both of our current compost heaps, 160901 and 160910 have now reached stable equilibrium. The two graphs below show the complete “heap lifetime” temperature against time. The tail of each chart is now reasonably steady, suggesting they are now “mature”. It’s between five and six weeks since we first built these heaps.
The complete “lifetime” temperature profile of compost heap 160901 started on the 1st September 2016. The second probe was first at a different level within the heap, and then reallocated to monitoring outside temp at the start of week 37Temperature profile of the heap using chicken manure slurry, heap number 160910, showing the much faster burn initially
In both of these there seems to be a reasonable evenness through the pile when both temperature probes are active, the temperature recording tips of the probes were set in the centre of the pile horizontally, and at about 1/3 and 2/3 from the top of the compost heap material.
We had a quick look at 160901 compost under the microscope a little while back and it was very exciting!
Fungal hypha in heap 160901Bacteria and protozoa, magnification 400x in heap number 160901Another fungal hypha
Although the temperature profile wasn’t up to scratch this heap has rotted down well, so it was turned into the small container to free up the big container for the next heap. Temperature sensors were reallocated to heap 160910 but box AS retained and long probe inserted, second probe is set to monitor ambient.
The end result of this turn: we moved the heap to our smallest compost bin as it had shrunk down so much.Before this second turnWe carefully took out the middle to ensure that a part of the heap that had not been fully heated in the centre had its turn.We wrapped the heap up in mypex woven weed control plastic to insulate it, ensure plenty of space for air flow.
The temperature of this heap was still falling back so more urine added Thursday 8th, 1 part urine to 3 parts water, total volume approx 2 watering cans.
The temperature of this heap was falling behind so urine added Wed 7th, 1 part urine to 3 parts water, total volume approx 2 watering cans. Thanks to members of our Community Supported Agriculture Scheme for generously supplying the urine (some particularly dedicated members even bring it to the farm from home!)
This heap turned Tuesday afternoon. Used fine mist on the spray to rewet some of it
Composting bin removedDetail after top layer removedSeparating the different sections of the heap to ensure all parts get heated in the centre at some point.Detail of above.
50% grass and clover with some nettles and comfrey
50% wood chippings.
Approx 15% N but estimated from the grass clover mix at about 50% grass, roughly equal mix that and green leafy (including relatively high nitrogen comfrey and nettles) and woodchip.
This was seeded with (very small!) soil samples from Staverton Thicks, Rendlesham forest and Captain’s Wood, all old, well established woodlands. We did this in the hope of introducing a wide soil food web to our heap, and subsequently to the soil. When we looked at these soil sample from the woodlands under the microscope they were certainly far richer in soil life than the soil at The Oak Tree at the time!
shredded evergreen shrub leaves
So the heap was made up of :
30% green leafy shredded conifer leaves
30% grass, clover nettles & comfrey
40% woodchip
Shredded conifer foreground and grass and clover background
Good initial progress but this was not sustained. Perhaps this should have been turned on the first Monday, rather than the Tuesday
Compost heap temperature profile: both probes were in the centre of the heap.
Review of what went wrong with this heap…
What happened – did well in reaching temperature, so sufficient N to get there, but no staying power. Possible causes:
Exhausting N by turning a day late?
Poor mix with insufficient N in the first place due to a lower clover to grass ratio than assumed?
possibly there is something too woody in the evergreen leaves?
possibly would have benefited from additional insulation to be able to turn earlier to avoid exhausting nitrogen?
