Thank you all! The head of lettuce thing was throwing me off. We picked leaves of spinach and romaine today and they were tasty!

As it gets hotter the lettuce will become more bitter. I prefer the small greens to letting it form a head. Just pick as you need it.

I pick spinich small. It keep reproducing. Not sure of any thing scientific but it seems to last longer into the season when I do this.

Re lettuce. I pick the outside leafs, which allows the inner ones to grow and mature and extend the harvest time. I never pick a whole head, but I have romaine, not iceberg.

These are cool weather plants, so if they look good you can go ahead and pick them. Lettuce can bolt when it gets really hot.

You should start picking them as soon as they're big enough to be worth picking. They're not going to get any better in this heat!

I've planted vegetable gardens before but this is the first year I've tried leafy greens. My spinach and lettuce are growing nicely! How do I know when to harvest them? I assume the lettuce should be picked as a head. How about the spinach? And after I pick them, the plant is done, right? I know, these are stupid questions. Thanks for any help you can offer!