Saw Dust and Wood Chips in Yard
Following up on your answer here. http://extension.oregonstate.edu/question-of-the-week/wood-chips-mulch I had several trees cut down and stumps ground up which created a lot of wood chips. In the front where I would have grass, how long would the chips tie up the nitrogen and prevent growth if I mix the chips in with the soil? In the back I was thinking of using a pile of chips from the chipper (with a lot of pine needs) and chips from stumps to help fill in a low area that would eventually become a garden spot. It's currently filled with English Ivy that we would remove first. How many years before these spaces would be usable and is there something like compost starter that I could mix in to help speed up the decomposition? Or is this just a bad idea in general?
Clackamas County Oregon
Thank you for your question about your mulch. The answer to "how long before you can grow plants" varies, depending upon the amount of sunlight, water, depth of the wood material and availability of soil microbes. Some experts say this can last from 3 to 5 years. (It may also depend upon what type of tree the material is from: hardwoods take longer than softwoods.) And because you had this ground up so small, it will tie up nitrogen longer than had it been chipped. However, you might want to read Dr. Chalker-Scott's article about the subject here: https://s3.wp.wsu.edu/uploads/sites/403/2015/03/wood-chips.pdf
If you pile this material on top of the English ivy, it may save you the trouble of removing it, since it will keep it from obtaining light and water. So, as you saw from the first article you read, it really isn't recommended as a soil additive, but, except for thepurpose of suppressing weeds, should only be used to mulch around woody plants and create pathways. The rest, you might be able to find someone to buy it!