Mar, Apr, May, Jun, Jul, Aug
At its best:
May, Jun, Jul, Aug, Sep, Oct
Fill modules generously with seed compost and level off so they're filled to the brim, then sow one or two seeds in each – you can always pinch out surplus seedlings later.
Sprinkle vermiculite or sieved compost to cover the seeds, then sit the tray in an inch of water to soak till the surface feels damp. Remove the tray from the water. Cover with a clear plastic lid or clear plastic bag. Put in a warm place to germinate.
Pot on seedlings once the second pair of leaves (or 'true' leaves) appear. Ease each seedling out with a dibber or pencil, handling by the leaves to avoid breaking the stems. Pot each one into a 7.5cm pot of multi-purpose compost.
Tall lettuces such as 'Bionda' or hearting lettuces like 'Webb's Wonderful' are best started off in seed modules.