Yay gardening thread! You know how some people have this problem where all the Sims they make kinda look the same? That's me with traits, because most of my Sims love the outdoors and want to do gardening things. And even if they don't, I make them garden anyway. ?
For anyone wondering about profitable plants, I know that dragon fruit and blackberries are often mentioned. Personally, I've found some flowers to be very worthwhile as well, like lily, rose, orchid, and crocus if you have Seasons.
If you're having trouble grafting things like dragon fruit and orchids (like they never spawn after combining plants): If you're not against cheats, I would use bb.showhiddenobjects. You should be able to find plants in the debug menu without having to go through dozens of seed packets either.
My legacy family also has a massive (flower) garden. I'm only starting the third generation, and it's not even hard to make money now. The garden pulls in 10k everyday. I don't have Seasons yet, so everything grows outside all the time.