Lesson 4
Season extension — fleece, cloches, and microclimates
Set your region to personalise this lesson.
You can buy yourself 4–6 weeks at each end of the season with the simplest equipment: horticultural fleece (£10 for a roll), cloches made from plastic bottles, and a sunny wall.
South-facing brick walls (north-facing in the southern hemisphere) absorb daytime heat and release it overnight — pots against them can be 3–5°C warmer than open ground. This single trick lets temperate balconies grow chilli, basil and aubergine reliably.
What buys you what time
- Single layer of fleece over pots overnight — protects to about −2°C (3–4 weeks extra in spring/autumn).
- Cloche (plastic bottle or glass jar) over individual seedlings — protects to about −1°C.
- Cold frame or mini greenhouse — 6–8 weeks extra each side, can grow winter salads.
- Sunny sheltered corner against a south wall — effectively one climate zone warmer.