Winter growing and heating without electricity

In short

• A tunnel with a single layer of film is only 1–3 °C warmer than outside at night; on a clear night sometimes even colder.
• An inner tunnel or fleece over the beds does more than any air heating: heat the plant, not the whole tunnel.
• Water in barrels and jerrycans absorbs heat by day and gives it back at night; it works best in a small space.
• Never a stove, gas or paraffin (kerosene) heater, barbecue or generator in a closed tunnel without a flue. Carbon monoxide kills without warning.
• Knock snow off at once, while it is falling, not the next day.

What's inside

Chapters

1. What a winter tunnel can really do
2. Where the heat goes
3. Layers: a tunnel inside a tunnel
4. Double film and insulation
5. Water as a heat store
6. Compost and manure as a heater
7. Soil, walls and the lean-to
8. Stoves, heaters and carbon monoxide
9. Snow and ice
10. Winter routine
11. Most common mistakes
12. Printable checklist

Worksheets

• Heat calculator
• Winter protection materials
• Winter temperature log
• Hard frost night and safety
• Winter tunnel calendar
• Winter layout sketch