Grass clippings from a weed free lawn make a great feeding mulch but….

Use lightly. Best when combined with a rich carbon source: leaves or untreated sawdust. Used alone, they make a good feeding mulch. Applied too thickly, grass clippings can decay into a slimy pulp, get very hot, and burn plants. Sprinkle lightly, no more than 1 inch thick directly onto beds from the lawn mower catcher. Layers can be added gradually.