kitchen_gardens

I grew lettuce for the first time this year. I had a really great crop, but it is getting to the end of its usability - the leaves are tough and bitter, not appetizing for a salad-full. I knew that summer heat would do that, but we have had a very cool and damp June, so I wasn't sure how long I'd be able to get use out of my lettuce beds.

So I'm wondering, did the cool weather prolonged my crop's life span? Also, is there anything I can/could have done to keep it usable, or does lettuce just reach a point of "old age" where it's not usable anymore, no matter how mild the weather is?

And another question - one of the lettuce types I planted was iceberg lettuce. Forgive me if this sounds silly, but I'm used to a nice, tight ball of iceburg lettuce like you might find in the store. Why didn't my iceberg look like that?