Designed originally for the English gardening market, these greenhouses have now been made available on the U.S. Market. The EasyStart 4x6 hobby Greenhouse can be used to keep established plants safe during the winter months, or provide a protected growing environment for delicate seedlings. Green houses such as the EasyStart and similar ones have a 4 millimeter twin-wall or single-wall layer of polycarbonate glazing. While these are excellent for providing a safe and habitable growing environment for plants are not recommended for serious gardeners trying to grow plants during the winter.