I've been growing San Marzano Redorta tomatoes for nearly 10 years and I find them to be superior for sauce that the standard #2 grown commerically in Campagna and elsewhere. I'm starting an experiment growing Redorta hydroponically over the winter from saved seed, but adding to the nutrient solution pulverized volcanic rock similar to that from Vesuvius. (The Italians claim it's that volcanic soil that produces the best SM tomatoes in the world.) While I'm not using the scientific method here, I've grown the variety in my Massachusetts loamy clay for a long time and have an idea of its flavor. I'll provide photos and updates along the way, but I'd appreciate any advice members may have. Thanks.