My greenhouse is not a large one but with the removable shelving that my husband made and my son has since updated it is more than adequate. During the winter it is lined with bubble wrap, this alongside the small thermostatic electric heater seems to do the trick. I also have a fold up one, or if you like portable one for outdoors, I use this in the spring to harden off the young plants, usually when the Tomato and Peppers are pushing for space.
During the winter the greenhouse houses all the Fuchsia cuttings and mother plants, also in February / March the French Marigolds that I grow for use especially in the greenhouse during the summer, as the Aphids do not like them, for the last 20 years since growing these in the greenhouse I have never had to spray. Long may they continue to do their job.
The seedlings that I start off in the propagator in the lounge, once they have two sets of leaves, are transferred to the greenhouse. Must admit the Lounge doesn't look very good in February until all the seedlings are moved.
I grow Sungold Tomato, they are so sweet even the Great Grandchildren eat them like sweets.They are great in salads, that is if you don't eat them before they get to the kitchen.
We have tried a few varieties of Tomato but always come back to Sungold, they are really prolific. As with all tomato the secret to stopping them from splitting is watering regularly and not overwatering.
We grow in large pots, I find this easier to manage and feed weekly with Phostrogen.
At the end of the season I save the compost for transplanting the Fuchsia from the baskets to pots for overwintering in the greenhouse, I feel the compost is so rich it is worth using again, have done this for some years without any problems, maybe I am just a tight wad.
On the opposite side I grow Peppers (Capsicums) from seed.
I use in salads, casseroles and especially in the spicy chicken dish that is a family favourite, this also includes Chili, the secret is not to make it overly hot, for me that is.
Last year I was surprised, as this was the first time I had grown Capsicums how easy it was, don't know why I expected it to be more tricky. I will if as successful this year freeze the spare as I am given to understand they freeze well. (saw same in the supermarket freeezer section)
I grew as the small bushy plant, it was the first time of growing these, this coming season I shall try the larger variety. Over the years I find use both the above more and more in so many dishes. I love being able to nip out and pick as and when.
French Marigolds I grow for use especially in the greenhouse during the summer, the Aphids do not like them, for the last 20 years since growing pots of these in the greenhouse I have never had to spray. Long may they continue to do their job. I take seeds in mid summer when they are good and dry, just ready for dropping, placing them in a large plant saucer to finish drying off. Later about September, I in place in a paper bag, rare things these, more often than not an envelope, I keep this in the garage as I inderstand they like to be kept cold in winter, some folks place in the bottom of a Larder Fridge for a time.