In my crop rotation turnip follow garlic. After garlic there is a lot of nitrogen to draw back to the surface. All kinds of brassicas can do the job, since they have very fast and deep growing roots.
As I’m fond of the juici sweetness of turnips, that’s my first choice. I find the turnips sown after the garlic more sweet and juicy than the springsown.
I also grow a other brassicas after the garlic, this year kale and winter radish.
The turnips in the picture are Ljungdalen, a swedish heirloom. I grow other varieties, including Orange Jelly (thanks to Patrick www.patnsteph.net/weblog ). I hope to harvest seeds from Lungdalen next year.