For the cost of a package of lettuce seed, I'd sure give it a try. The benefit of a cold frame is that the soil inside there will warm up nicely during the day, and release the heat slowly at night. You'll certainly need to make sure it doesn't get too hot during the day - I would think high teens would be ideal growing conditions for lettuce. If a real cold snap threatens you could always throw some blankets over top at night to help hold in the heat even more.

Plant some radishes and onion sets in it too, Gil - and you got yourself a salad!

Cool thanks gals, I planted the lettuce out just now. It's currently 10C inside the frame (I have a thermometer in it) and it's 5C and cloudy outside so it's doing its job. I'm not fond of radishes but I do need to get some new onion sets because I pickled all mine last fall. Mmmm pickled goodness...

Make sure you keep us posted on when it germinates, and how it works out

My boys built themselves a greenhouse several years ago, when the oldest was about 12. They just came and got me, and showed it to me - already done! With a few revisions, it's still standing 5 years later, and they are kind enough to let me use one small area of it. I usually plant lettuce and spinach in there by mid-April, and we have salad before the end of May. We don't add any heat but if nasty weather threatens I do throw a blanket over the plants. Your cold frame should work well. Lettuce tolerates freezing quite well. I've had it freeze crispy in the fall and the plants were still fine when they thawed.

Connie

Operation Lettuce is a success so far... I have little lettuce sprouts and I have also added some gazanias and Shasta daisies to the cold frame to harden them off.

I just bought some lettuce seeds last night and was just wondering about when to do them! I guess I know what I'll be doing in a minute (or two)! LOL I'll be doing radishes too and maybe some onions.... good idea!

Can you plant onions sets out now? There is no snow left, but the soil is very wet and we mt still get frost and snow. The guy at the store said that onion sets can be planted as soon as you can see the soil

I do not have a cold frame, but can I plant lettuce now under cloches (plastic ones?)

Onions are cold tolerant but I don't like to plant anything in the garden until the surface of the soil has dried out. Compacts it too much. My cold frame is on my deck with pots in it, guess I should have mentioned that. I am very careful to open it during the day so things don't fry. Cloches should be ok as long as you remove them when it's sunny and warm.

Here's the ugly beast itself...

n.b. not that it matters but I accidentally typed "gazanias" when in fact it was Gaillardia I put in the cold frame. oops. I also have foxgloves in there.

Very nicely built cold frame Gillian! It sure seems like the plants inside are really enjoying it. I was going to throw some lettuce and spinach seeds in the only dry patch in the garden and see how they fair. But, I ran out of time yesterday after clearing out some of the flowerbeds and dividing waterlilies, etc., so hopefully tomorrow will be able to do it if it's not too wet after the rain we're getting now. If I let my spinach go to seed in the fall, guaranteed there will be sprouts next spring and they aren't coddled at all.

My cold frame is usually just on the grass, but i was wondering if it would work to put it on the cement patio. The cement would retain heat better, wouldn't it? I'm going to drag it over this weekend and set it up. Mm - i need more plastic for it. Must remember that when we go to town this evening.

Just let the spinach reseed for next year. I have been doing so for a number of years in the garden at the end of the lane.
For supper tonight I am mixing my own spinach with romaine lettuce (from the store) to make a salad. My spinach patch must be about 8' x 15' now already. We will never use it all, in fact, when people visit me for the next few months...we will have to make a trip to the garden before they leave and harvest some spinach leaves.

I have both lettuce and spinach that reseed. I'm not sure what kind the lettuce it - I got it from my Dad's self-seeding lettuce, it might be black-seeded simpson. Some of my lettuce is up already - just 2 leaves but it won't take long, and some of my spinach wintered over. Yummy! I've seeded an assortment of different lettuces already, and I'm hoping to get more kinds that will self-seed. They're all in the flowerbed by my house - we eat more salad if I can just pop out the door and get it, and it's a (very) big flowerbed. It also holds all my fresh herbs, winter onions, etc, tucked in among the flowers.
Connie