Possible Clues:

• Knock up the top and cut off the bottom of the veg.
• Carrot's paler cousin
• Plant Dad gets gardener finally to cut
• After a knock-up they have a point up - that's the root of it (7)
• Places blame for criminal charge when turning over plant
• Strong-scented root vegetable
• Regular bargain at the greengrocer's?
• Dad doesn't finish wild sprint for vegetable
• Vegetable requiring an even cut
• Usual loss leader at the supermarket?