Hah! I grew them longer ago than that! Several years. I think we didn't have good enough summers to bring out their true flavours. I grew some in the greenhouse, some outdoors, and the ones that ripened last were really good, the ones that ripened first weren't particularly nice at all. I almost pulled them all up. But we went away on holiday and when we returned I tried some of the later ones, and they were lovely. So forcing them and bringing them on early doesn't do any good, unlike say cherry tomatoes, which being far smaller ripen more quickly. Black Russians get to quite a size. The later ones grown naturally outside also didn't have the grainy 'velvety' texture that merlotgran mentions. I grew them for two or three years before I was able to persuade DBH off them, he loved them for their colours, which varied hugely from black all over to a streaky brown/green/blacky-purple.