The Vegepod Hothouse Cover (aka Winter Cover, Greenhouse Cover or Propagation Cover) is made from clear non-permeable PVC. They are custom cut and hem-sewn to size and shape so as to sheath easily and snugly over all three Vegepod canopies. The covers create a greenhouse/hothouse environment for plants, allowing sunlight to come through and trapping the heat in, whilst keeping extreme cold and precipitation out. This not only protects plants from the sharp cold, winds, frosts and snow but also creates a micro-climate to enhance growth. For extreme cold or poor light environments, users are recommended to take off the existing canopy mesh before sheathing the clear PVC cover on. This rids the 17% shade supplied by the existing canopy. For climates where it is not so extreme, then users can simply sheath the covers straight over the top of the existing mesh. These winter covers are also used for protective early plant propagation, raising of seeds/seedlings, early season planting or season extenders, summer crops into autumn. Please take care to remove covers as soon as periods of warmth begin or you will otherwise typically 'cook' your plants.