Cold frames and cloches are transparent-roofed enclosures, built low to the ground and used to protect plants from cold and windy weather. They act as a mini-greenhouse, letting in sunlight and reflecting radiant heat back on to the plants. In the spring, they are most often used for hardening off plants raised in a greenhouse, whilst in the winter they are useful for overwintering the seeds of hardy annuals sown in autumn, protecting winter flowers and sheltering vulnerable alpines from the wet and cold weather.

Polytunnels are particularly valuable in areas such as the vegetable garden, where low-cost protection is required and visual appearance is not important. Its tunnel-shaped frame covered with heavy-duty transparent plastic sheets open at each end provides plants with protection from the wind and winter cold, but without creating the warm conditions of a greenhouse. Although they are primarily intended for growing crops at ground level, some polytunnels include staging for plants in pots or grow bags.