Q: I have a compost pile that is heating up very nicely. Should I be concerned with using grass clippings that may contain weed seeds?
A: If the pile gets hot enough (140 degrees for 3 days) you’ll kill the weed seeds with heat. Get a long-stemmed compost thermometer to check the temperature at the center of the pile. If the pile is smaller than 4′ x 4′ x 4′ it won’t reach a high temperature. Grass clippings contain nitrogen and contribute to heating up the pile, hastening the destruction of their offspring. Be sure to keep the pile moist and turn it regularly. If the pile only gets warm despite your best efforts, weed seeds won’t die immediately but they will decompose over several months time.