It look to me like your lettuce is trying to bolt. Not sure of your zone but here in Georgia lettuce is usually grown as a cool weather crop. I usually plant lettuce in the mid to late fall. Warm temps will make lettuce start to bolt or send up a flower stalk. What type is it?

Sorry, but I think your lettuce is "bolting". This means its starting to make a flower and will then set seeds. Either it stayed in it's pot for too long or the fertility of the soil is poor or the timing was just wrong.

You can still eat as many of the leaves as you want but soon enough it'll just be a stem and flower bud.

Lettuce really needs to be planted every 3-4 weeks all season long to if you want to always have a fresh supply.

-Mark

I'm up near Pittsburgh. It's been pretty hot lately(~85), so that kinda makes sense. It's about half in the shade and half out...is there anything I can do to help it out besides wait for fall?
Thanks a bunch!

Nope. The leaves by now will be bitter and unpleasant, and nothing to be done about it. Pull it out, plant more in August.

Also that looks like an iceberg head lettuce. These can be hard to grow to full heading maturity in most climates. A leaf lettuce might be a better choice.

Lettuce can be confusing at first. If you've never grown it, you might not understand the difference between leaf lettuces and heading lettuces. Leaf lettuces will not make a head, or clump, like you were thinking, so if that was a leaf lettuce, you waited too long in vain. Even heading lettuces can be hard to judge, at least here. They form up into heads suddenly one day then within a week have passed into bolting (like yours) it often seems. If you really want to grow a lettuce head, I would recommend trying a romaine. They are pretty obvious when they have headed up. Otherwise leafe lettuces are harvested a few leaves at a time, from the outside, think like what all those "spring mixes" look like. Lettuce harvested too late can be the toughest, most unpleasant tasting stuff, but lettuce harvested early will be so tender you won't want to have to buy it from the store anymore. :) good luck!

It's quite possible to harvest leaf lettuce by the head. It's harvestable that way much more quickly than an iceberg type.

My favorite lettuces are the Batavia types, particularly Nevada. They make a head that's looser than iceberg, not as open as leaf types. And they do it quickly, yet hold w/o bolting longer.

Still, any lettuce is eventually going to go to seed. That's it's life cycle completing.

My Skyphos is a red butterhead. It is still sweet and crisp. It is the best I have ever grown. Stokes Seeds sells it.

Maybe it's a zonal thing, but my leaf lettuces never made anything that looked like a head. I agree you can harvest the whole plant, but it will always be loose and open, not tighly wrapped like a head lettuce.

I grow Summertime, and in a good year it will definitely make a head. Not a bowling ball like you find in the grocery store, but a real head, loose but closed and the size of the big softball.

Summertime stands longer than a lot of my other lettuces.

This post was edited by ltilton on Wed, Jun 26, 13 at 22:07

Why would you want a big ole head, when you can get so many cut and come again lettuces? You just snap off as many leaves from the outside of the plants and they will keep growing back until they bolt.
The cut and come again varieties such as romain, red leaf lettuce, and others also make a prettier salad and are much higher in nutrients than iceburg lettuce, which is almost all water. The deeper the color, the more nutrients. They also have much better flavor IMHO
Go to a better (organic) store where the staff actually knows their veges and ASK! They don't mind answering questions, even about growing your own (at least where I go) if they know the answers. If not, they will usually find out for you!
You can also go to farmers markets to see what is in season in your area and jot it down to plant for next year. ASK them when is best to plant what.
Otherwise, go to your extension offices' web site and you will probably find a planting list for your neighborhood.
Lastly, I get a LOT of first hand info from Master Gardeners at our local county fair! They give out charts and lists of planting times for your area, edible flower lists and more! (of course we are in a very organic ag area!)
I'm sorry, I really can't tell you about back east planting, cause I'm in the west where we can grow pretty much all year round. Good luck and Happy Gardening!
HTH Nancy

Some of us have more substantial notions of what makes a salad and use up several heads at a time of all varieties.

The only variety I pick by the leaf is the iceberg, because one person in the house wants it for sandwiches.

People should grow for the way they want to eat.

My lettuce is now bitter and tough. I was told you can cut it off and plant the root part it will grow again. Is this true ?

Another great classical lettuce is Bibb. A good discussion of overall lettuce culture, with photos, can be found here:

Biodynamic French Intensive Method

Here is a link that might be useful: Alan Chadwick