Feed-grade sorghum (S. vulgare, S. bicolor) is a perennial. It is sown in the spring and the stalks cut down as green forage for animals.

Grain sorghum, on the other hand, is an annual and is used as a food source for humans. It is differentiated from the feed-grade variety by its smaller size and more compact panicle (tassel). It is sown in spring and harvested while the grains are still moist; therefore it must be dried quickly.

There are other types of sorghum; their names reveal their various uses: paper sorghum, broom sorghum, etc.

However, beware of Sorghum halepense, known as Johnson grass or Egyptian millet, which is an invasive weed.