The covered area [greenhouses, tunnels, etc.] varies according to the climate and the objectives of each microfarm. To produce all year round, it can be about 30 to 40% of the overall cultivated area. Note that although this proportion seems relatively high, it is rather low compared to the usual standards, per worker, for organic market gardening.
Double protection against the cold is generally practiced in winter so as to extend the growing season. [Ed: for example, fleece covers inside the greenhouse.]
At Bec Hellouin, the covered area (of the order of 450 m2) is small compared to the number of workers. But the growing surface (covered area multiplied by the number of rotations) is relatively significant: 450 m2 X 5 rotations on average = 2,250 m2. The high number of rotations enables this costly investment to be more profitable and reduces the required area under cover.