Beta vulgaris (90 days) Sugar beets are a natural source of sugar and where most of the sugar industry derives its sugar from these days. Beets are up to 1 foot long and can weigh from 3-5 pounds. Seeding rates are from 10-15 lb. per acre. That means you need to thin them to make sure they have enough room to grow. Approx. 1,500 Seeds per ounce.