Learn which plants thrive in your Hardiness Zone with our new interactive map!

How to Compost Pine Bark

By Tracy Morris ; Updated September 21, 2017
Pine bark can be turned into compost for potting soil or soil amendments.
pine bark image by dvest from <a href='http://www.fotolia.com'>Fotolia.com</a>

Pine bark can be used as both a mulch around ornamental trees and shrubs or as a soil amendment when mixed into the soil to improve it. Using rough, irregularly shaped amendments such as pine bark can help to aerate compacted, heavy clay. But wood amendments can lock up nitrogen in soil until it decomposes. The solution to amending soil with pine bark is to decompose it first through the process of composting. Composted pine bark is pH neutral and full of nitrogen.

Shred pine bark into chunks that are 1 inch in size or smaller. Smaller chunks of pine bark will decompose faster. You can rent a wood chipper to accomplish this.

Rake pine bark into 1-foot-tall windrows (rows). Add 1 lb. of urea per cubic yard of pine bark and wet until the bark is as wet as a wrung-out sponge. Pile a second 1-foot layer of pine bark over the first. Wet this second layer and add more urea. Continue to mix and add 1-foot layers of pine bark until the windrows are 12 feet tall and at least 3 feet wide. The bark must stay consistently 50 to 60 percent wet to prevent the formation of fungus that grows on dry bark.

Turn the windrows once weekly by shifting each windrow to the right of its current location with a shovel. Mix the bark while you shift the windrow and wet it so that it is between 50 and 60 percent moist again. The bark should be reduced to loamy compost in 10 weeks.

Add lime, starter fertilizer and micronutrients such as iron, zinc and manganese to the compost before amending the soil or using the compost as potting mix.


Things You Will Need

  • Wood chipper
  • Garden hose
  • Shovel
  • Pitchfork
  • Urea
  • Lime
  • Starter fertilizer
  • Micronutrients


  • If the composted bark develops fungus, the fungus will cause the bark to repel water instead of absorbing it. This will create problems in the composting process. Compost that develops this fungus will have trouble absorbing moisture. Plants placed in potting mixes and amended soil with this issue will not be able to absorb water at the root level.

About the Author


Tracy Morris has been a freelance writer since 2000. She has published novels and numerous online articles. Her work has appeared in national magazines and newspapers including "Ferrets," "CatFancy," "Lexington Herald Leader" and "The Tulsa World." She holds a Bachelor of Arts in journalism from the University of Arkansas.