[whitespirit66]

My Webbs Wonderful lettuces are coming on nicely, but the slugs have already had a nibble.

I don't really want to use chemicals, so what are the alternatives?

[Mitsy]

I'm using beer or slug pellet traps. Just an empty yogurt carton with either in the bottom sunken into the ground. Its working for me 

[peapod]

theres loads of thought out there for organic slug deterrents, some good,some not so good.  You can buy organic slug pellets, but they are pricier than normal 'blue' ones. Copper strips, baked crushed eggshells, coffee grounds, gravel mulch are all ideas people use,as well as the beer traps
Personally, I cant get away with anything other than pellets, or Id lose the majority of my crops to snails

[Libby]

I had quite a few Little Gem lettuces eaten, along with cut and come again leaves  .  I put sticks at the corners of each row and ran string down the length of the row to form a rectangle. Pulled quite tightly, this lifted the lettuce leaves off the floor and kept them in an upright position.  This has worked really well and I haven't lost any since.  Worth a try. 

[Faz]

Or failing that a large bag of slug nails, a hammer and a few hours on a damp evening should help