In the Berkshires considerably west and north of Woods Hole, the alternative energy people used manure, water containers, and stone to make heat for the winter in their greenhouse. They had no trouble getting tomatoes to fruit, walked around passing them out for free near the Red Lion in Stockbridge. If that manure was used as fertilizer as well as heat in Woods Hole, the nitrogen kept the plants from fruiting, (and grew great leafy veggies) not the lack of solar radiation. In fact, the Berkshires Bunch had to paint their greenhouse glass with whitewash to keep the daytime temps reasonable, that should have raised hell with the infrareds. Gareth the ChileKnight