Special equipment is used in the growing of many horticultural plant. This equipment is used to start plant at seasons when out side condition are unfavorable, to grow plants to maturity at off seasons of the year, and for the propagation, by maturity at off seasons of the  year, and for the propagation, by seed or vegetative methods, of plants that require special treatment.

Types of Special Equipment :

There are several  different types of kinds of special equipment. The kind or species of plant to be grown, the length of time the entrapment is needed during a season, initial cost, operating expenses, and other similar factors are considered in deciding upon equipment to be used. 

Forcing Hills and Plant Protectors :

Certain structures are designed to cover the  individual plants in the field. They are known as forcing hills or plant protectors.

Types :

Several types are used. Formerly, one made in the form of a box, usually 12 inches square and 12 inches high with a pane of glass for cover , was used extensively. The initial cost, cost of storage, breakage and labor required to place them over the plants and removed them have all tended to discourage their  use.

Other types of plant protectors, however, are used for growing plant in the open. Small conical cover made of translucent paper or plastic are used commonly. Some plastic cover are flexible and are designed for using once only others rigid and may be used reputedly.

Uses :

Plant protectors and forcing hills are used to protect plants form untimely cold weather and form damage by wind. They are also used to increase the soil temperature to a degree which is favorable for the germination of seed. Workers in Arkansas have shown that muskmelon seed planted early in the spring germinate quicker when plant protectors are used, be cause of the higher prevailing soil temperature. The plants which got an early start ultimately produced marketable melons at a slightly earlier date than plants in locations where no covers for crops that produce a heavy yield of a valuable product form an individual plant. The tomato and muskmelon are examples of such plants. On the contrary, it would be impracticable to use forcing hills for carrots or radishes because the unit return from an individual plant of such crops is too small to justify the expense for labor and material.

Cold Frames and Hotbeds :

Cold framers are designed primarily to protect plants from cold without the use of artificial heat. Hotbeds differ from cold framers in that they are provided with artificial heat.

Uses :

Cold frames and hotbeds are used widely in the starting of vegetable crops, and to a lesser extent for cuttings. Cold framers are used primarily in protecting plants against a few degrees of cold, usually in early spring. They are also useful in providing protection against wind and excessive rainfall, and in the hardening of plants prior to transplanting to the field, a practice that is discussed in the chapter on transplanting. In some places, crops are started in cold frames and, when the water permits, the frames are removed and the crops continue. Plants may be grown in hotbeds at seasons when it would be too cold for them in cold frames; Oftentimes, Young plants are started in late winter in a hotbed and later as the weather becomes milder they are transplanted to the cold frame. After a period of growth there, they are finally moved to the field when outside weather conditions have become favorable.

Construction :

Cold frames and hotbeds are constructed in the same general manner. They are usually made of wood or concrete. When wood is used, the structures can easily be made so that they are movable, This makes it possible to set them up at different places each year and to store them during off seasons. Insulating the walls, particularly those made of wood, makes them more effective in retaining heat and providing protection. This is cor manly done by lining inside walls with heavy paper or by banking soil against the outside of the walls. The standard width of cold frames and hotbeds is 6 feet; the length is variable, depending upon the space needed. Cold frames and hotbeds should be located on the south side of a building or other barrier which will provide protection from north winds. The lengthwise direction should be from east to west. The north wall of the structure should be 6 inches higher than the south wall. This facilitates shedding of water when the frame is covered. It provides better exposures to sunlight in late winter and early spring and also provides some protection form north winds. The bed or floor of the cold frame or hooded should be even with, of slightly above the surrounding ground level to ensure good drainage. When concrete is used to make a permanent structure, the wall usually extend well into the soil and therefore special provision should be made to provide adequate drainages by the use of a sand or  gravel fill and tile drains.