I always attributed more to soil and sun, because I grow great tomatoes easily in my garden every year. This year I did have to fertilize a few times, and they are only ripening now. I’m on the Canadian Prairies so not exactly subtropical. And I’m not that good a gardener either, cucumbers are often a struggle for me and my beets always get demolished by birds. And it’s been a good 4 years of various weather here and still, nice tomatoes. I wonder if there are some more locally adapted strains you could try?