I planted some comfrey near my tomato plants because it's supposed to help with production and overall health of the tomatoes. Also, I know that you can take some of the leaves and fill up a 5 gal container, then add water, let it soak (outside!!) until it's "ripe" and then use the liquid as a fertilizer for your tomatoes. You can also put the old leaves on top of the dirt/mulch around your tomato plants and as it breaks down, the beneficial nutrients will leach down into your soil. As of yet, I've not been able to try any of this out because my plant only has about 5 leaves on it! Thought I'd share with you, though.
