Earlier this Spring I went to visit my local sawmill and they were willing to give me a truck load of wood chips and a separate garbage bin full of the smaller bit sized sawdust for my property. Initially I was just going to use the wood chips for my paths and walk ways as it is a great weed killer. I would take some of the finer broken down wood shavings and powder and put it in the cracks of my driveway so as to kill the weeds, works great. But then I thought what about the garden. It made sense to me to use it as a form of a mulch, so I decided to do a bit of research and see what I can do. This blog will describe my successes and my challenges with using sawdust in my garden.
This is my Goji Berry Bush, in the spring I sprinkled woodchips around the base on the container and as you can see it did not do so well, despite mixing bone meal and coffee ground in with it. More investigation into why at a later post.
As part of my research I found this interesting Blog with an article about using sawdust written in 1947 by a farmer.
http://us.naturespath.com/blog/2009/07/10/sawdust-my-slave
So first lets talk about sawdust in general. IT IS A SLOW TO BREAK DOWN. It takes about a year to fully decompose, however clay based soils could benefit as they are a fast soil to lose their nutrients and break down. Sawdust is a mulch that drains NITROGEN from your soil, and many plants require nitrogen, so you want to avoid using it as a mulch with plants that require an abundance of Nitrogen. If you want to use sawdust with these plants, simple add a mixture of Bone Meal or coffee grounds to your sawdust to help balance the mulch.
DANGERS
Do not use pressure treated wood shaving, chips, or sawdust as they are chemically treated and harmful to your soil. Also, you may want to avoid using Black walnut, or any walnut and cedar as it has JUGLONE a component that will stunt the growth of your plants, especially tomatoes. However if you are looking to eliminate rooted plants then this is exactly what you need. I have also determined that if you place a good portion around the base of tree trucks and shrubs it can cause rot. Lastly do not place near your home as it may attract termites. Avoid using the fine sanding powder of sawdust as it will just cake on the soil and will never really break down and cause your plants to have not drainage in the soil.
BLUEBERRIES AND STRAWBERRIES are acid loving plants that could benefit from sawdust as a mulch. Simply place 1-1.5 inches of sawdust sprinkled around the top of the soil careful not to put a heavy layer around the base.
MY EXPERIMENT
This summer was a terribly wet summer which brought out many many slugs. Sawdust is a great way to deter slugs from your garden, so I thought I would try it on my potatoes this year, that I had planted in my raised beds. A low and behold so far I have no signs of slugs eating away at my leaves and the plants appear to be doing well. So great result. I did however make a mix of bone meal with my sawdust. If you are going to do a larger garden area of a mixture of plants, the ratio is 1 pound of Nitrogen based compound like coffee grounds or bone meal to 50 pounds of sawdust.
Sawdust is also a great compound to grow mushrooms in. If you are willing to experiment and monitor your environment and conditions, such as temperature and humidity then it can produce some amazing results. Please see my blog post about growing mushroom from earlier this year.
Well folks there you have it, yet another experiment of sorts that I bring you my results. I plan on using the sawdust again this fall/winter to mulch my beds to get ready for Spring.
Happy Trails