Sugar beets are very tough to grow. Just ask any beet farmer. Many times they jump the gun plant early and the seed gets pounded in by spring rains. This combined with the touchiness of the depth of planting keeps the local farmers gray haired. If you want to try it, just check with a local farmer. He will likely let you buy some of his Roundup ready seed. This way you can keep your field clean to maximize the yield.
A friend of mine grows Mangel Beets. They are a little bigger and much more forgiving.
Good luck either way, but try talking to your farmer friends.