Ventilated plant protector

A plant protector comprising a housing adapted to substantially enclose a plant or group of plants to be protected, an elongated ventilation opening in a wall of said housing, an elongated panel extending adjacently along said opening and having one end pivotally mounted on said housing wall to turn about a pivot axis at one end of said opening, said panel pivotally moving in a plane parallel to said housing wall between a position closing said opening and at least one other position selectively uncovering said opening, means for controlling the position of said panel comprising a thermally responsive device mounted within the housing so as to be subject to the air temperature within the housing, said device comprising an expansible heat sensitive coil having one end anchored on said housing wall, the other of said coil attached to a pivot pin extending between said housing wall and a bracket thereon, a motion transmitting control arm secured at one end to the pivot pin and pivotally connected at its other end to the other end of said panel adjacent the other end of said opening whereby a variation in air temperature within the housing may actuate said coil to move said control arm for pivoting said panel relative to said opening, the axis of the coil being substantially parallel to said pivot axis of the panel.