Miniature greenhouses are fairly obviously smaller versions of traditional greenhouses. These mini greenhouses are usually assembled in the early spring to help provide a favourable climate for cool weather plants right through autumn and winter months. Some of these greenhouses are moveable and can be taken apart and stored until the next use the following year to save them from harsh winter conditions.
Cold frames and hotbeds are a common type of miniature greenhouses, which utilize the sun's energy as heat. In hotbeds, the heat from the sun is supplemented by heating cables or fresh manure. During the day the sun's energy is transmitted through the clear lid and trapped by the soil bed. At night the cold frame minimizes the heat loss and keeps the greenhouse well insulated. These structures are usually open-bottomed. They also have hinged lids that provide easy access to the plants within. The lid is also the only source of ventilation for the plants. These mini-greenhouses can be made of plastic, aluminium or wood.
A terrarium is another type of miniature greenhouse. It consists of a transparent container that is tightly fitted with a cover or a lid. In it, plants are grown in a bed of soil and the cover helps prevent the loss of moisture. Ventilation is provided by removing the cover for a few minutes everyday to refresh the atmosphere inside the terrarium.
Mini greenhouses are usually located in an area, which receives ample sunlight, sans shade. They are also placed on a slight slope as this gives better drainage. Hotbeds are generally located over a bed of fresh manure and soil. Since these greenhouses require water and electricity, they are sometimes constructed as lean-to or attached structures. These greenhouses are placed leaning against the house, so that one wall of the house forms the back of the greenhouse.
The size of these greenhouses depends on space, plants, and other personal requirements. A wide greenhouse is not suitable for harvesting and weeding. These greenhouses can also be equipped with various accessories, for example, a maximum-minimum thermometer, which is used for temperature control. You can use blankets, shade cloths or bamboo window blinds to protect the plants from damage caused by extreme temperatures.