Sowing lettuce seeds

Although it is still quite early, I always like to start a few lettuce seeds off in pots on the windowsill:

These are:
"Intred" - Described as a 'compact Little Gem' with outer reddish purple leaves.
"All the Year Round" - A compact butterhead variety. One of our favourites from the mixed variety pack that we grew last year.
"Lakeland" - Another compact variety with a 'crisp head'.
We have not grown Intred or Lakeland  before so it will be nice to try something different.
Last year we sowed our first hearting lettuce seeds on 8th Feb and picked the first ones towards the end of May (approx 14 weeks? we didn't record the exact date on the blog). I might try and sow some more seeds in a couple of weeks time just to see if they mature over a shorter timescale (if I remember, that is!).