Greenhouses with vertical air vents on the roof are collectively referred to as sawtooth roof greenhouses, which are referred to as sawtooth greenhouses for short. The air vent of sawtooth magnetic greenhouse can make the ridge straight to the gutter and become full sawtooth. It can also be from the ridge to a part of the roof or from a part of the roof to the gutter, which is called semi sawtooth. The former is sharp sawtooth and the latter is blunt sawtooth.