Last week saw our first two light frosts; it is remarkable how consistently they arrive in the second week of October, normally followed by a mild spell that, in Devon, can last until Christmas. Our late courgettes, planted on a gentle southerly slope, survived as the frost drained and settled in the valley below. It has been a perfect autumn so far with plenty of dry, bright weather for harvesting roots, sowing green manures and preparing the farm for winter. Meanwhile, the polytunnels have been replanted with rocket, mustards, salanova lettuce, land cress, dandelion greens, claytonia, chards and beets which will be harvested as young leaves for your winter salad bags. They are mostly cut by hand which allows us to take up to four harvests from the most vigorous.
The high capital investment of polytunnels normally dictates that they are cropped intensively with no break for green manures; a recipe for trouble according to most organic theorists. Instead we maintain soil fertility and structure with composts and well-rotted manures, plus an occasional top up with chicken muck for more nitrogen, while we control most pests with introduced natural predators. This could be regarded as a compromise in organic principles but I’m pretty sure that our tunnels produce food with very low environmental impact, because they crop so heavily and reliably, because we never use heat, and because they are growing crops which would otherwise be imported. After 25 years I can say with some confidence that the system works; in organic farming, as in most things, observation, learning and evidence is normally a better guide than dogma. The tunnels also let us offer continuity of employment through the winter and give our staff a break from the hardship of the fields. We love them. Were it not for the visual impact and concern for our neighbours, we would unquestionably put up more.