Apopolyctic Thumb of Black Death

I have a black thumb, in gardening terms. My garden last year was a flop. Sure, I had an invasion of Tobacco Hornworms, and then an invasion of jack rabbits. Not to mention the invasion of both canine and kids. But a good gardener would have had at least a few seeds sprout. But look what I found growing OUTSIDE my garden in the gravel. It's lettuce! Two lettuce seeds fell to the ground, made it through winter, and are now two little plants! I had nothing whatsoever to do with this, but it makes me want to try again. (Does it matter that I'm pretty sure Steve the cat uses my garden as his toilet?)