I have heard conflicting advice about using fresh wood chips in the garden. Some say do not use as they tie up nitrogen, and others say that the nitrogen gets released back. Can I use wood chips?
Thank you for contacting Toronto Master Gardeners. This is a great question. It’s true that wood chips, as any organic matter, do require nitrogen to decompose. However, years of research have shown no nitrogen depletion to the soil and plants. This myth, and other common myths about mulch are discussed in Maddening mulch myths by Linda Chalker-Scott. Over time, nutrient levels of the soil are enriched by the decomposing wood chips.
Arborist wood chips are considered by many to be the best mulch for trees and shrubs. Benefits of using coarse Arborist wood chips as mulch include:
- the mix of materials in arborist wood chips (bark, wood and leaves) provides varying decomposition rates
- good weed suppression when used at a depth of at least 4 inches
- contain no harmful chemicals, unlike commercial dyed mulches
- absorb water for better water retention and slower release of water to the soil
- can usually be obtained free of charge from a local arborist
- reusing wood chips is great for the environment as it keeps the material out of landfills.
More information can be found in Professor Chalker-Scott’s Fact Sheet: Using Arborist Wood Chips as a Landscape Mulch
In answer to your question, Yes, you can and it’s highly recommended that you do use arborist wood chips as a mulch for your garden.