A lettuce seed is so small it can't be planted straight into the ground, so it starts life with a plant raiser.
The farmer gives the seed a special chalk coating to make it into a pellet. The farmer then plants the pellet into a cube of peat called a plug, where the lettuce begins to grow.
The farmer keeps the plug in a room which is high in humidity and temperature until the seed germinates. It is then moved to a glass house to help it grow into a plant that's about 6cm tall with four leaves. At this stage it's moved outside to get used to the outdoors. This whole process takes about 34 days.