Effects

• Grass clippings used in a high quantity pose a high risk of baking your worms, unless used sparingly in thin layers or in an outdoor worm bin to deliberately heat it in winter. As a green compost material, grass clippings decompose via thermophilic composting. Heat-loving bacteria raise the compost temperature to 100 to 150 degrees Fahrenheit, notes the Ohio State University Extension website. Compost worms do better in temperatures under 77 degrees, according to biologist Mary Appelhof in "Worms Eat My Garbage," and temperatures 90 degrees and higher cause them to try to flee to avoid dying.
  
  

Considerations

• Use grass clippings cautiously in a worm bin, such that brown carbon-rich materials outnumber the grass by a 30:1 ratio. Or compost the clippings in an outdoor compost bin first, and bring them to the worms only when they have cooled off and dried out, which converts them to a brown material.
  
  

Expert Insight

• Avoid composting grass clippings treated with pesticides in your worm compost bin. The residual effects of the pesticides may last from one to 12 months, notes the University of Missouri Extension website.