Harvesting involves removing the economic parts of crops from the field after maturity. It is important to harvest at the correct time, which is generally physiological maturity. Physiological maturity occurs when translocation of photosynthates stops and can be identified by external symptoms varying by crop. Harvest maturity occurs one week later when drying is more complete. Threshing separates grains from plants and should be done carefully to avoid damage. It can be done by hand, with animals, or with machines.