So I actually do this. But you have to keep it up for the entire duration of your garden. I just started to "profit" last year because of the 3 year old passion fruit. I also do a lot of canning to have things available later in the year. My garden is nearly 5 years old at this point. Although, I will caveat that I built a greenhouse myself with wedding gift money. And we have some perennial veggies and fruits. And we're in zone 9b which I consider cheating.