There are several ways in which plant growth can be gauged, the metrics vary for different types of plants. An apparatus known as an auxanometer measures the increase in plant growth. Some other ways of assessing and measuring the plant growth are – measuring the height of the plant, examining the size and number of the leaves, estimating the rate of growth with that of fresh plants, and detecting the rate of growth with dried plants.
An auxanometer is an apparatus for measuring the increase or rate of growth in plants. In the case of an arc-auxanometer, there is a wire fixed with the plant apex on one end and a dead-weight on the other. It passes over a pulley that has a pointer attached to it. When the plant's height increases, the pulley rotates and the pointer moves on a circular scale to directly give the magnitude of growth.
The "rate of growth" is a derived measurement obtained by dividing the length of growth measured by the auxanometer, by the time said measurement took.
Sensitive auxanometers allow measurement of growth as small as a micrometer, which allows measurement of growth in response to short-term changes in atmospheric composition. Auxanometers are used in the laboratory, the field, and the classroom.
Koningsberger invented the auxanometer.