Some time back I poked a thermistor into the composter and found the temperature was a few degrees higher than the surrounding air and with the aid of a few metres of bubble-wrap this increased to around 25 deg. C. in early Autumn. Being a mechanical engineer, I pondered ways of tapping this heat source with coils of copper pipe, pumps etc. which sort of makes sense if you like that sort of thing. A few days ago I was thumbing through my 1900 edition of “Cucumber Culture for Amateurs” and found this:
It’s a cold frame built over a composter in the form of a brick chamber, the bricks provide some insulation and the heat passes up to the space above. The text suggests that this may have been the earliest means of providing additional heat for plant cultivation. It refers to the process as “fermentation” whilst I think the modern term is aerobic digestion.
It’s mid April and the nights are still cold, whilst I have managed to get sixteen viable tomato plants, not much else has germinated. As a quick and dirty experiment, I sowed four seed trays with celery, peppers, chillies and cucumbers and simply put them in the composter, stacked on an old tray. The composter came to life at the start of the month and is pleasantly warm inside, everything else in there being unpleasant. I have no idea what the outcome will be.
I’m pre-occupied with house renovation at present, but a combined composter and cold frame might be a project for the Autumn.
“Cucumber Culture for Amateurs” is a good, but curious read. I’m fond of a cucumber sandwich and pickled cucumbers make a good salsa, but the green houses and heating arrangements described would cost the equivalent of several thousand which is a high price to pay for a comedy vegetable.