Organic vs. Inorganic

• Mulch can be organic (bark, shredded wood, straw, grass clippings) or inorganic (rock, stones, brick).
  
  

Organic Advantages

• Organic material provides an ideal environment for earthworms and other beneficial organisms. As it decomposes soil becomes loose, improving water retention and stimulating root growth.
  
  

Inorganic Advantages

• Rock is available in a variety of sizes and colors. It provides texture and interest, is permanent, is fire resistant and does not change the composition of the soil.
  
  

Organic Disadvantages

• Organic mulch breaks down and has to be replaced. While mulches such as cedar are aromatic, others can produce an unpleasant odor.
  
  

Inorganic Disadvantages

• Smaller rocks tend to sink into the soil and are hard to keep clean. Bags of rock are extremely heavy and can be hard to handle.
  
  

Application

• Organic mulches are applied 2 to 4 inches deep. After settling, an additional 1 to 2 inches may need to be added once a year. Rocks are permanent and applied to a depth needed to cover the soil.