Hot beds are usually located near the farm buildings and near a good water supply with south and Southeast exposures for sunlight. Generally farmers use hot bed made of wood and cement. These beds may extend 30-45 cm above the surface of the ground on the backsides and 15-30 cm in the front, thus giving a slope. Hot beds have different heating systems. (i) Manure heated (ii) Flue heated (iii) Hot water heated hot beds (iv) Electrically heated hot beds.
(i) Manure heated:
Fresh manure mixed with one post stress are placed in pit where hot bed actually is needed with optimum moisture condition for fermentation and steaming
(ii) Flue heated:
Heated by hot air conducted through flues from a fire box located at one end of the bed.
(iii) Hot water heated:
Most satisfactory method as the temperature can be controlled more easily, but is expensive.
(iv) Electrically heated:
Electricity is passed through the specially constructed cable, consisting of electrically insulated resistance enclosed in a flexible metal sheath. Initial cost is high but beds are always ready for use and they are easily manipulated and readily removed.