We never say never, so it’s certainly possible that you can grow parsnips in Southern California (see the zone list at the top of the page, right of the photo). The end of season frost tends to sweeten them but it’s not nec for growing/reaching maturity. The need a long growing season—and you folks have that in spades (not so here in New Hampshire). It would be worth your while to consult your local cooperative extension service to talk about parsnips in your area, especially if you are in a microclimate (in hills or a valley). Click here and choose your state to get specific info: https://www.almanac.com/content/cooperative-extension-services
We never say never, so it’s certainly possible that you can grow parsnips in Southern California (see the zone list at the top of the page, right of the photo). The end of season frost tends to sweeten them but it’s not nec for growing/reaching maturity. The need a long growing season—and you folks have that in spades (not so here in New Hampshire). It would be worth your while to consult your local cooperative extension service to talk about parsnips in your area, especially if you are in a microclimate (in hills or a valley). Click here and choose your state to get specific info: https://www.almanac.com/content/cooperative-extension-services