What do I do with lettuce that has gone to seed?

Gather the seeds and let them dry out. place the dried seeds in a glass container and wait till next spring. this info comes from my wife and i hope it is accurate for you.

In Hawaii it is warm enough to grow lettuce year round. I don’t know if that is true of your climate. Yes you can use the seeds for another round of planting. It is always worth it to keep seeds!!! Like @john65pennington said, dry them out and then store them in a dry place (do not let them get wet) until you are ready to plant them. If the climate is suitable, you can let them fall and reseed themselves usually perhaps unless you have poor soil quality. I store all my seeds in old jam or peanut butter or spaghetti sauce jars.

Thanks, I’ll give it a shot!

Awww, wish I had know this yesterday before I dumped a head of lettuce. Will remember for next time.

I suggest planting it.

I would compost it, then it will grow in the compost heap, along with the cherry tomatoes.
Soon you will have a salad.

Does that mean it is ‘rusty’ so to speak. I don’t care for rusty lettuce. Is that what you mean?

No…I mean it has been in the garden so long that it is growing a stalk and flowers.