Sumo Citrus Seeds For Sale . Today, sumo citrus is grown in big greenhouses in the san joaquin valley in california on small acreage farms. Honestly the best way to start a citrus seed is to just sow. SUMO ORANGES (2 CT) New England Country Mart from newenglandcountrymart.com I've got two small seedlings going now. A sumo citrus orange will run you $1.69 at trader joe's, which is. Public since 2011, but it's quickly become a favorite.