Yes, you can put a fire pit on grass -- but you need to take a few precautions. For one, you'll want to make sure the grassy area you choose is level, so the pit doesn't tip over. You'll also want to avoid damaging your grass: The high temperatures coming from a fire pit cause heat stress to your grass, which can discolor or kill it. The best way to protect your grass from damage is to put a barrier between the fire pit and the grass. You can simply put some patio slabs underneath the fire pit, or buy a heat shield or a fire-resistant mat. Whatever solution you go with, you should make sure to move the fire pit around frequently, so as not to damage grass in one location.