Reader Laurence J. Belosevic mentions corn gluten as an alternative to chemical herbicides, and I thought others might be interested in learning more about using corn gluten for organic weed control. EarthEasy states that "As a weed suppressant, corn gluten acts as a natural 'pre-emergent' - it inhibits seed germination by drying out a seed as soon as it cracks open to sprout." I found another good source of information about corn gluten on green-talk.com.