sunflowers are up

One of my favorite flowers are sunflowers. They are so cheerful to look at when they are in bloom. Some years I have good luck with them, some years not so good. Something always eats the tender shoots just as they are popping up out of the ground or if they do manage to grow the woodchucks eat the leaves. So this year I am trying the greenhouse effect. I planted the seeds and covered them with a cut in half soda or water bottle. I kept the bottle on the plant until it reached the top of the bottle. So far it seems to be working. Now if we could just have some sun.