Size

• While red wigglers typically run 3 to 4 inches long and 1/4 inch thick, Euros, or super reds, as worm hobbyists call them, grow 3 to 8 inches long and as thick as a pencil.
  
  

Considerations

• A worm bin containing red wigglers will do best at around 70 degrees Fahrenheit, while Euros prefer a range from 60 to 70 F. Texas A&M University reports that the larger size of the Euros makes it easier to pick them out of the bedding when harvesting the compost.
  
  

Expert Insight

• Bentley Christie, a worm hobbyist in Southern Ontario who runs the online site Red Worm Composting, notes that Euros reproduce more slowly than red wigglers, but are more tolerant of poor bin conditions and low food levels.