There are five types of lettuce, romeine or cos, leaf also called loose leaf, crisp head, stem also called asparagus lettuce and butter head. There are many different varieties within the five types. such as the Bibb lettuce shown in the picture to the left.

Lettuce is easy to grow in hydroponics and does not require as much lighting as other crops such as Bell Peppers. Lettuce harvest time varies greatly with variety ranging from 40 to as much as 80 days for lettuce like the red iceberg. Most lettuce varieties are harvested between 45 to 55 days.

Lettuce if grown outdoors in summer can be a little bitter and are best grown in temperatures 74 to78 degrees or cooler depending on variety.