If you want to make turnips like a pro, you would love the tutorial by artist Vicky Guile in the February '09 issue of Artisans in Miniature magazine.
Visit http://www.scribd.com/full/11554245?access_key=key-2g1aii8ggieklh4jh66y and you will find the tutorial on pages 42 - 43.
Artisans in Miniature: http://www.artisansinminiature.com
Vicky's website: www.njdminiatures.com
Vicky's blog: http://www.njdminiatures.blogspot.com
Vicky's Flickr: http://www.flickr.com/photos/njdminiatures
Vicky's Etsy store: NJDMiniatures.etsy.com
