I started growing some basil, mint, terragon and cilantro on a window box. My problems is that they grow big and fast and I can't use them fast enough. Eventually the plants gets too big and old, with fewer small leaves, mostly stem, and it'll start to go to seeds. Any idea on how to slow them from growing so fast? I don't really want to pick them and make sauces or oils, I'm interested in perhaps pruning techniques? Or is this something that I have to replant every year?