A series of plant species of sweet grasses (poaceae) are described as wheat. There are a number of varieties which are adapted to different climates and grow to heights of about 0.5 to 1 m. Wheat makes greater demands on climate, soil and water supply than other sorts of cereal. Although wheat (depending on the variety) is frost resistant to approx. −20 °C, overall it prefers a temperate climate. For people in many countries, wheat is a staple food (bread cereal).