Incidentally, I purposely got tomato plants that would not produce huge tomatoes. It has been my experience that larger tomatoes take too long to ripen in the desert heat, so they split, go bad, get eaten by insects, or all of the above, before we get to eat any. So this year, I planted 6 roma tomato plants, and one grape tomato plant. The tomatoes we're getting are mostly very small roma tomatoes, or very large grape tomatoes. But we're getting a lot, and they are very good.
So, in the picture to the left, do you see any watermelon? I know there are three that I could see when I took the picture, but in the picture, I can only find one for sure. The largest is about the size of a mini-basketball. We had a watermelons about that size (12 in. diameter?) before we even noticed that there were any watermelons actually on the vine. Then we saw the other four or five all of a sudden. They hide well.