The easiest and low-tech way of adding the microorganisms from compost is to extract them fro mthe compost using water and a mesh, then spray the water – in our case using watering cans. You can spread the compost itself, and there’s much to be said for that, but it’s more stuff to wrangle and needs to happen before you plant, ideally. Since we are going to test areas on already growing plants, extract it is. Compost tea is a way of getting more microbes out there, but it is technically harder and we don’t have the gear. Extract it is, then. The rate seems to be about a good handful per 5 gallons, we used half an IBC, ie about 500 liters, which is 110 gallons. So we need about 20 times as much
Start with a wodge of compost in a net curtainand 500 litres reasonably clean borehole water (so no worries on chlorine or chloramine)
We made a bag by putting the compost in the middle of the net curtain material and tying up the top with a releasable cable tie.
You can see the brown of the humic acid leaching out of the compost into the waterthe end result is a dark brown chocolate colour
The successful compost is ready – it has now fallen to roughly ambient temperature.
unfortunately the temperature logger failed when I was on holiday so I don’t know what the profile was as it cooled down. And yes, it didn’t spend three times three days above 55C – more like three days and two days. There’s still more to learn here.
Time to look at this and see what sort of microbial stuff is in it. I shook this up with about 20 times the amount of water and put a drop on a slide
fungal hypha and bacteria
According to Elaine Ingham’s rules of thumb this is probably a good sort of soil fungus, because if the little round cocci are 1µm in diameter the fungal hypha is about 4µm. I could see that this one was slightly tan coloured, but the incandescent lamp of the microscope plays havoc with the white balance of the camera, making everything bright yellow.
This next one is narrow and clear, so not good in the morphology rule of thumb that fungi < 3µm in diameter and clear are undesirable soil fungi.
I saw no protozoa or micro-arthropods. That’s either because there aren’t any or because I didn’t recognise them. The dilution is high, – it appears that Ingham starts at 5:1 so I’m four times less likely to see these at 20:1.
The high-nitrogen activator should typically be about 10% of the composting materials. These are typically animal wastes – I have used real chicken crap, pelletised chicken crap, and clover. With the chicken manure each time I have scored a fail, whereas the clover was a success.
pelleted chicken manure
I suspect the trouble is that it’s hard to mix a concentrated activator properly. For starters it’s not pleasant to do, which discourages it being turned in right. The pelletised stuff is easy to distribute evenly, but even then it seems to lead to localised action.
pellets seem to turn white
The pellets seem to go white, like dog crap used to go white when left on the footpath in the 1970s. This leads to a fast and furious burn on the composting front, but with no staying power
pelletised chicken crap – leading to a fast ramp up but no staying power – the dip was when it was turned
The clover was more evenly spread – somehow I need to find a way of spreading the others more evenly. Or maybe go for the urine, preferably from carnivorous humans (there is more N in protein). In Ben Easey’s Practical Organic Gardening (Faber, 1955) he says dilute this with water 1:20 which should make for a better distribution. So I’m going to steer clear of using crap, because I am a wuss and don’t like dealing with it and it’s too concentrated anyway. Clover or urine will be my activators of choice 😉
Joanne’s note Oct 2016:We subsequently (in later heaps) used pelleted chicken manure mixed with water and stirred into a slurry. It took a lot of water to do this! Poor old Richard has a very sensitive sense of small (tough on a small farm with animals!) so he had to leave the rest of the team to finish up building the heap when we started to add the slurry…
If at first you don’t succeed, try again 🙂 The requirements of Elaine Ingham’s thermal composting are quite demanding, keeping the heap at over 55C for more than three days to kill weed seeds and pathogens. The previous attempt got really close then seemed to dry out, this appears to be a issue with using a lot of woodchip which is a difficult material to wet. This time I used less of it.
more green material with this heap
I used a higher proportion of green material, and more of the high nitrogen clover too. I filled the wheelbarrows with woodchip and then added water until it overflowed, then left it to soak overnight
this achieved over 55C for three days – the dip is when this was turned on Thursday evening
After it had been over 55C for three days I turned this heap, wetting the material as it was turned over. I should be able to turn this again on Monday, assuming it holds above 55C
Time to put some of the learning from the last time into practice, with thanks to Polly for help with wrangling the materials –
Raw materials
The clover which it the high-nitrogen component because it fixes N from the air is on the black plastic. Loads of wood chip is in the bin and the wheelbarrow. First we put sticks in the bottom to improve airflow because the whole point of thermal compost is to keep things aerobic
base of sticks to improve airflow
We needed to wet the material. In the video tutorials Ingham recommends standing the material in water overnight. We wetted is using a fine spray on the hose
We have a lot of clover, which as Cotswold Seeds describe, are plants that fix nitrogen from the air in combination with Rhizobium bacteria living in root nodules. Since I’m going to use this for the high Nitrogen component instead of chicken crap I wanted to see if there were any active root nodules – after all if there were no bacteria or we had used nitrogen fertiliser there would be no nodules.
Clover root nodules
The good news is there are root nodules – so the clover is ready to fix nitrogen. The first sample nodules have no red in them, even when dissected, which seems to mean they weren’t actually fixing nitrogen. This only starts when the soil temperature is above 8C. However, taking a second sample from the same patch showed better results.
opened nitrogen fixing root nodule shows a distinct red colour
Looks like with these you have to open the nodules to see the red colour of leghemoglobin , they’re not particularly pink from the outside. Leghemoglobin transports the nitrogen to the plant from the nitrogen fixing bacteria.
Getting ready to have another go at composting the Elaine Ingham way after the first couple of attempts at thermal compost didn’t go right, I dissected the old material to find out why.
the heap dropped to about a quarter the original size
On the plus side, the material reduced in volume to 25% of the original volume. That in itself might be telling me something, in that perhaps i hadn’t packed down the original pile enough – the composting bugs are small, and they need to be in contact with the compost to munch it, there is such a thing as too much air gap 😉
looks particularly dry, except in the very middle
Only the very middle was wet, and did not smell, so it looks like this pile largely dried out from the outside, it probably didn’t go anaerobic, and indeed was active enough to nut the smell of the chicken crap used as the high N part.
Compost isn’t something I’d even given much thought to, I got it in bags from B&Q and job done.
Compost. On a farm scale you get it wholesale, not from B&Q 🙂
A long time ago I never bothered and used garden soil, perhaps an instinctive predilection towards natural farming – as exemplified in shumei.
I visited the guys doing Shumei farming in Wiltshire – being Japanese they had this image of Mount Fuji on the site, though the December rain doesn’t do it justice
At school I learned that soil has micro-orgnaisms that somehow worked symbiotically with the plants, but pretty much everything in the decades that passed seemed to run counter to that – perhaps my schoolbooks were from an earlier era.
In the UK air temperature is normally measured in a passively cooled Stevenson screen. The louvred design of the screen allows air to flow around the thermometer. The trouble with a polytunnel is there is no wind at all, as a result the sun heats the sensor up and without airflow you don’t know by how much.
By running a computer fan driven off a solar panel I can move enough air past the sensor to exchange the heated air from the sun shining on the sensor. For the sensor I use the standard Chinese supplied DS18B20 encapsulated in a stainless steel tube
Dallas DS18B20 epoxied in a stainless tube housing, from a Chinese Ebay supplier
The sensor is housed in a 6cm piece of white plastic waste pipe
sensor mounted in centre of white waste pipe
The fan is mounted at the top of the pipe, designed to pull in air from below; this way the sensor is not heated by air passing the fan motor, and the airflow works with the natural tendency of warm air to rise. I’ve tried to keep the airflow as unimpeded as possible.
side view – the flange for the fan is made from a piece of wood glued to the pipe
Looking at the results there is a difference of a few degrees
the difference opens up a few degrees at high temperature
between the aspirated sensor and another sensor mounted on the outside of the plastic tube. They track at low temperatures but not when the sun is shining – the difference here is about 6 degrees, even in March, before the vernal equinox. It is remarkable just how much the air temperature swings – 27 degrees on a couple of days which still have hazy sun.
Sensor mounted in polytunnel
Weatherproofing the sensor is easier in a polytunnel because as well as the wind not blowing, it also doesn’t rain. I can use a cheaper indoor solar panel, the one I used is a 12V 1.5W unit, Maplin L58BF bought on sale for about £6, not the £20 they seem to be charging for it. even £6 is a little dear! I extracted the flashing blue LED and series diode to maximise the power available to the motor. This also charges the battery of the temperature sensor dual unit, which reports back to the collecting station using Ciseco’s XRF every 10 minutes.
Solar panel schematic
The computer fan was a 12V brushless unit but I run it at about 7V, we’re not after blowing a gale through the tube. It will start at 5V. The Zener is there to limit overcharging of the 4.8V NiMH battery pack in the electronics to about 4mA. It only reports every 10mins so this is enough. The 1N4148 diode stops the battery discharging back through the fan and solar panel in the night. I should really measure what the leakage current of that Zener is 😉
I used a PIC 16F628A driving a Ciseco XRF to send the temperature data from two sensors back. Nowadays I would use the Ciseco RFu which includes an Arduino and low-power standby mods to make this cheaper.
Other implementations
This is a nice weatherproof design – I can’t work out if I missed a trick with using just one plastic tube rather than a coaxial design. Lots more ideas here.
Postscript (July 20 2015)
five months of data
This rig works reasonably well; if power were available I’d run the fan all the time in daylight for a more rigorous result on summer cloudy days. The biggest problem in a polytunnel is that they are shockingly dusty places, and you have to sponge the dust of off the solar panel every month or so.
Nowhere in the datasheet does Texas tell you “hey use this fixed regulator as an adjustable”. However, I’m used to being being able to do that with the venerable 78XX series – indeed Texas tell you that you can do that with the 78L05 datasheet in Fig 14.
Adjustable 78l05. Bear in mind the shocking Iq of 3mA that’ll stand you up an extra 3V if resistor R2 is 1k, keep ’em low…
Given that there’s an adjustable variant of the LP2950 that appears on the same datasheet (the LP2951) I laid out a PCB and being the lazy sort I am I assumed that since I was using a load of these parts in their 3.3V KY5033 variant, where I wanted an 8V stabilised voltage for an audio mic amp sourced off a 12V supply I can simply do the LM317 trick, drop in a couple of resistors from the output to ground and the ground pin to real ground, job done.
what I planned…
For this I made R1 6k8 and R2 10k.I expected an output voltage of 3.3+3.3/6800*10,000=8.2V or near enough. I screwed up labelling the o/p 10V, mistakes happen…
What does that look like then?
Oy vey, about 4V of massive oscillation (I’m using 10x probes). At least it’s centred on the right value-ish. Let’s take that output capacitor out
Looking good, only 1V of oscillation, now at 370kHz or thereabouts.
So if you come here from Google wanting to know why the LP2950 doesn’t work as an adjustable reg, now you know. There is a tiny clue in the datasheet in the ground current variation
which varies by two orders of magnitude with a load current variation of 1000. This will be impressed upon R2, varying the target voltage – as more current charges the capacitor the target voltage will rise, then ease off as it is charged, making a handy relaxation oscillator.
There’s another clue that the output cap can give interesting results in this line
which actually specifies a ESR range, rather than less is better
No criticism of Texas’ product implied – these are great little fixed voltage regs with a low quiescent current and are my goto device for running 3.3V devices off a 5V rail because of that superb dropout voltage of 600mV max, across the entire range of load current and -40 to 125°C which is easily in spec off a 4.75V min 78L05. It’s just one less thing to worry about. Im future I won’t be a doofus and try and use one where a LM317L is called for 😉
