The Stewart Company's Heat and Grow thermostatic propagator came top in a recent Which? survey of windowsill propagators.
Products from six manufacturers were tested across a range of pricepoints up to £35. Each was subjected to similar conditions and scored for ease of use and how well they maintained the optimum internal temperature.

With a score of 69% the Stewart Heat and Grow thermostatic propagator came out on top.

Priced at £30, it features a built-in thermostat so the element will switch off at higher room temperatures to prevent overheating.