TIK - Sorry to say I don’t have the space or physical ability to keep my tomatoes from crossbreeding if they’ve a mind to. I do use heirloom indeterminate seed but typically pick up a few new unfamiliar strains at the local nursery each year.
I haven’t managed to keep my varieties separated and labeled as I did in younger years but I know most this year were cherokee purple, some brandywines and another heirloom I can’t recall. Against my rule of thumb I also put out 6 Celebrities this year because my brother recommends them as all he grows. He does not have time to garden as intensely as I but does get huge crops. My celebrities did not produce like his and won’t try those again. I do prefer to start my own from heirloom seed.
That said, I accept the fact that my tomato seed is “hit and miss” because my seed saved could be an unyielding variety.
I have a lot of well lit, non-freezing area affixed to the house due to a large glassed-in porch, a bit less than 500 sq ft and a glassed in balcony which is 240 sq ft. I bring in the healthiest of my small to medium tomatoes in pots. I also take cuttings to root in soil from healthy large tomato plants. I keep the cuttings under old aquariums while they root.
The seed I save I do choose from the plants I’ve brought in. I may miss great seed by not saving any from healthy large outdoor plants.
Over the winter when I see a plant that isn’t thriving but may have good side shoots coming off the root I may cut and root the side shoot to have a fresher start in spring. Often, I’m tied up with other winter projects and don’t get around to rooting the new shoot and will just cut off the old plant come spring and replant the old root and new shoots. Either way, these over-wintered plants are my first producers in spring.
When I used to work at a greenhouse, they used to take numerous cuttings of geraniums, as well as growing plants from seed.
These cuttings too would be among the first to bloom; however the blooms would 'shatter' easier than those plants grown from seed.
Also, these cuttings, perhaps due to their weakness to 'shatter', would also send up more bloom replacements but lost their ability to withstand any cold.
The more reliable plants that would even withstand some light frost were those grown from seed, while the number of blooms would be about what you would expect.