It's been nearly two months - time to harvest my tiny crop of chioggia beets. They weren't very big: between 1 and 2 inches across. I chopped off the tops, gave them a good scrub and baked them in the oven for an hour. Unfortunately the rings fade into a dull yellow colour when baked but on the plus side their juices don't stain like the juice from purely red beets. Tasted great.