I always grow Winter lettuce but they take a long time. But I'm just an amateur

It depends on what part of California you are in, Moo. I would check with your local county Cooperative Extension. They will have a planting guide for your area, and you can probably translate that for your greenhouse by adding a couple of months to the planting times for the late summer and fall edibles, and subtracting the same for the ones planted in spring and summer. In some parts of the state, year round gardening may be possible, especially if the greenhouse is cooled in the summer.

Sorry Moo, I didn't realise you were "over there". I'll be there ( San Diego) myself in January. Can't wait to get some of your weather.

That is why I wanted to know which general region of California Moo lived in. Garden schedules are quite different in the Sierra Nevada, compared to the southern coast region, or the Mojave desert!