A hotbed is a biological term for an area of decaying

organic matter Organic matter, organic material or natural organic matter is the large source of carbon-based compounds found within natural and engineered, terrestrial, and aquatic environments. It is matter composed of organic compounds that have come fro ...

that is warmer than its surroundings. The heat gradient is generated by the

decomposition Decomposition is the process by which dead organic substances are broken down into simpler organic or inorganic matter such as carbon dioxide, water, simple sugars and mineral salts. The process is a part of the nutrient cycle and is ess ...

of organic substituent within the pile by microorganism metabolization. A hotbed covered with a small glass cover (also called a hotbox) is used as a small version of a hothouse (heated

greenhouse A greenhouse is a structure that is designed to regulate the temperature and humidity of the environment inside. There are different types of greenhouses, but they all have large areas covered with transparent materials that let sunlight pass an ...

or cold frame). Oftentimes, this bed is made of

manure Manure is organic matter that is used as organic fertilizer in agriculture. Most manure consists of animal feces; other sources include compost and green manure. Manures contribute to the fertility of soil by adding organic matter and nut ...

from animals such as

horse The horse (''Equus ferus caballus'') is a domesticated, one-toed, hoofed mammal. It belongs to the taxonomic family Equidae and is one of two extant subspecies of ''Equus ferus''. The horse has evolved over the past 45 to 55 mi ...

s, which pass undigested plant

cellulose Cellulose is an organic compound with the chemical formula, formula , a polysaccharide consisting of a linear chain of several hundred to many thousands of glycosidic bond, β(1→4) linked glucose, D-glucose units. Cellulose is an important s ...

in their droppings, creating a good environment for microorganisms to come and break down the cellulose and create a hotbed. (The digestive systems of ruminants such as cattle and sheep destroy and use all cellulose in their food, and their droppings remain cold and do not heat up.) Hotbeds employed in gardens are generally simple in application. Experimental research from Neugebauer (2018) concluded that other forms of organic waste, such as compost, can be used in place of manure in hotbeds, providing not only means of promoting plant growth, but also an ecologically friendly way to dispose of waste. Data from this study does suggest that the amount of heat released by hotbeds does decrease after some time, however. Additionally, although not experimentally supported, the article from Neugebauer (2018) provides an idea that perhaps the carbon dioxide released from the hotbed is taken up by the plants, further improving the rate at which the plants grow. Some egg-laying animals, such as the brush turkey, make or use hotbeds to incubate their eggs. By extension, the term ''hotbed'' is used metaphorically to describe an environment that is ideal for the growth or development of something, especially of something undesirable.

References

Biodegradation Composting Ecology Horticultural techniques Horticulture {{Horticulture-stub