Lettuce is most often grown as a leaf vegetable, but sometimes for its stem and seeds.

Plants generally have a height and spread of 15 to 30 cm.

Lettuce plants have a root system that includes a central taproot and smaller secondary roots.

Today there are seven different cultivars and numerous varieties grown, the most common cultivars being leaf, head and Cos or romaine, all of which were grown:

  1. Leaf – Also known as loose leaf, cutting or bunching lettuce has loosely clustered leaves and is the most widely planted. It is used mainly for salads.
  2. Romaine/Cos – Used mainly for salads and sandwiches, this type forms long, upright heads and is the most often used lettuce in Caesar salads
  3. Iceberg/Crisphead – The most popular type in the United States, it is very heat-sensitive and was initially adapted for growth in the northern United States. It ships well but is low in flavour and nutritional content, composed of even more water than other lettuce types
  4. Butterhead - has a loose arrangement of leaves known for its sweet flavour and tender texture.