Two years ago I did a test in my garden where I covered half the garden in wood chips and used a no-till gardening method. On the other half, I continued to till and didn't add any wood chips. I wanted to do my own test to know if wood chips were beneficial for garden soil and the growing season or not… it's been two full years and I'm sharing the results of my soil tests in this post. Were the wood chips helpful or not?
There are so many things to learn about when you're first learning how to start a garden. Everything from these beginner gardening secrets to learning foolproof methods when garden overwhelm sets in (it's a real thing!).
It's also good to learn about companion planting, and how this can help improve the soil health of your garden, as well as how to create a garden plan for more harvest and less stress.
The deeper you get, the more you learn, and that's the beauty of gardening year after year!
Many people tout the benefits of using wood chips or adding a layer of mulch in the garden, and for good reason… but do the benefits always outweigh the potential drawbacks?
My initial concern when covering my garden in wood chips (and the main reason we only covered half the garden) is that the nitrogen would get bound up in the wood chips and depleat the soil.
From what I had read, as long as the wood chips were only on top of the soil and not mixed into the soil this wouldn't be an issue. But I just had to be sure so we did a side-by-side test and got three different soil tests from Simply Soil Testing just to be sure.
What is “Back to Eden Gardening”?
Originally coined by gardener and arborist Paul Gautschi, the Back to Eden method of gardening is supposed to mimic the forest floor where organic material continues to fall year after year and build up to beautiful, nutrient-rich, loamy soil with great water retention and little to no watering. I've previously written about this method for weed control here.
Depending on your gardening methods, your climate, and the types of crops you're growing, this may be a wonderful method, or it may not. We've been using both the Back to Eden no-till and tilling methods in our garden for the past two years (in different locations).
We wanted to do a true side-by-side comparison and see just what the differences were for us. I just got the soil test results from three different places in our garden and you may be surprised by the results, I was!
Why Use Mulch in the Garden
There are many benefits of using mulch in the garden. A few of which are:
- Less soil erosion
- Better water retention/less overall watering
- More plant protection
- Weed suppression
- An improved food web (worm habitat) under the soil
- Added organic matter & nutrients
- Better soil temperature control
- Reduces overall waste
Less Soil Erosion
Because wood chips will absorb excess moisture, during heavy rainfall or heavy waterings, the soil will remain and not get washed away.
This is extremely helpful for erosion-prone areas of your yard or garden that are on a hillside or are just at a slight angle where water would runoff.
Because wood chips retain moisture, they act like little sponges, steadily releasing that moisture during the heat of the day. They also help to insulate the ground (more on that below), so the moisture in the soil doesn't evaporate off as quickly.
Plants are protected from soil erosion which could cause their stems to be exposed or the stability of the crop to weaken.
Adding wood chips to your garden is a great way to suppress the weeds. Because tiny weed seeds have a hard time pushing up and through the wood chips, they simply cannot grow (not all, but most), therefore reducing the amount of weeds in the garden.
Furthermore, those weeds that do make their way through the wood chips will be easier to pull up.
It's important to note that you don't want to add wood chips over newly planted seeds for the same reason. They will have a harder time germinating and sprouting if they're covered with wood chips and your germination rate will be horrible.
Wait until your crops are established before adding wood chips as mulch up and around the plants.
Improved Food Web
Taking our queue from the forest floor, where leaves, decaying trees, pine needles and other organic materials constantly falls to the ground, there is an amazing web of mycelium underneath the top surface.
Adding wood chips to the garden helps to build up this strong living “food web” hiding out just beneath the surface.
Added Organic Matter
As wood chips break down year over year, they continually add to the organic matter in the soil, creating rich, loamy soil that's the perfect growing medium for vegetables and other plants.
Soil Temperature Control
As mentioned above, a layer of mulch will help control the temperature of the soil. On extremely hot days, the soil just below the wood chips will be slightly cooler. And once those temperatures start dipping toward freezing, the soil will stay insulated a bit longer.
Reduce Overall Waste
Because you can use other materials besides wood chips as mulch, you can really help reduce the waste on your homestead.
Have a fallen tree? Rent a wood chipper and harvest your own wood chips. Raking up a bunch of leaves in the fall? They make perfect mulch (as long as they don't just blow away!).
Look around your yard, I'm sure you'll come up with many items that can make great mulch, even if it's not just wood chips.
BONUS: Beautifies the Garden
When you add fresh mulch to your garden spaces, it adds a nice appealing look that's very tidy and purposeful. Because it also helps suppress weeds, when adding mulch year after year, you can help improve the look of your garden and lessen your overall workload as well.
Soil Test Results
Now the part you've all been waiting for… the results of the soil tests! Check out my other post if you want a more detailed look at how to test your soil pH and how to amend it based on the results read this post.
I ran soil tests in three different portions of my garden. I definitely took samples of the area that's been mulched with wood chips for two years and the area of the garden where we've continued to till and not add wood chips or any other form of mulch.
Then I also took a sampling from under our high tunnel where we added wood chips just last year. The results of that test were actually the most surprising! Read on to find out why…
Garden Plot Mulched with Wood Chips
- Nitrogen Level – 11 ppm (this is the higher end of “low”)
- Micro/Macronutrients – all very good! Each of the levels of nutrients (phosphorus, potassium, calcium, magnesium, boron, sulfur, and organic matter) were either in the very high, high, or medium-high range which I'm very happy about.
- pH level – 7.08 A vegetable garden is ideal between 6.0-7.0, so I'll add a little bit of elemental sulphur and this will come down just fine.
Garden Plot Not Mulched with Wood Chips
- Nitrogen Level – 24 ppm (this is on the high end of medium)
- Micro/Macronutrients – all very good in this garden area as well.
- ph level – 7.19 Still almost optimal, which with pH levels, if it's just a little bit over or under, it won't affect the growing season much. But when an area is significantly off, you'll notice much more struggle for your crops. This is especially important when you're growing plants like blueberries that like much more acidic soil! So know what you're planting and know the pH level that specific crop desires for the best results.
I have a theory on why both sides have differing results. Many people don't like to till because this can break up the mycelium and food web connection under the soil, however, when we till, we till back into the soil the green matter which will release more nitrogen back into the soil.
High-Tunnel Garden Plot Mulched with Wood Chips
It's important to note that the plot where we put our tomatoes is a new plot that was formerly wooded with evergreen trees which tends to make the soil a bit more on the acidic side to begin with.
After just one year of having this area mulched with wood chips, the results are as follows:
- Nitrogen Level – 46 ppm (this is on the high end of high)
- Micro/Macronutrients –
- pH level – 5.52 This is a little bit too acidic for tomatoes, so I'll be adding some lime to help raise the pH level.
My theory on why this area has a higher nitrogen level is that this area of the garden is covered and doesn't get the rainfall like the rest of the garden areas. I truly believe the rainfall is what washes away the majority of the nitrogen, even when the wood chips are on top of the soil.
Why Organic Matter Matters?
We like to have a high level of organic matter because, as it holds moisture and brings aeration, it also contains nutrients. As the organic matter breaks down into your soil it will continue to replenish all the micro and macronutrients.
More Gardening Articles
- Sheet Mulching the Easy Way
- Soil Remediation – How to Fix Tainted Soil
- Fall Gardening Prep – 10 Tips to Improve Your Soil
- Beginner Gardening Secrets You Need to Know
- Science-Based Companion Planting Strategies
- 13 Basic Steps to Starting a Vegetable Garden
- Hugelkultur Garden Beds (What, Why & How)
- How to Create a Garden Plan for More Harvest & Less Stress
- Planning a Fall Garden (28 Crops to Plant in August)
- How to Harvest & Store Potatoes (w/out a Root Cellar)
- Preventing and Treating Early Blight for Tomato and Potato Plants
So we’re you pleased with the Back to Eden mulching approach and plan to continue using it?
I’m wondering what you decided about the wood chip method? Are you going to continue to do it? I have done a little bit of it. We have very hard clay soil. I feel our dirt needs a lot of amending before putting wood chips on top. Otherwise, it’s too hard to dig and plant – I don’t think they would survive.
I am wondering too.
I was wondering the same thing.
Did she ever say whether or not she would continue to use wood chips??? I got to the end and didn’t see the end result? Are they good or not?
Hi what can you tell about container gardening see I used to have gardens but these strange little critter’s showed up one day and the were eating the stuff I planted so I can’t put anything in the ground right now I have tomato’s in pots 20 of them I would like to do more than just tomato’s but I i don’t have the knowledge and i really used to love gardening
It looks like you have a lot of grass, do you put that in your garden or into your compost pile? I’m in Western WA (Whidbey Island) and slugs are a big problem(even with a duck living in my garden)! I’m always looking for top dressing that won’t appeal to them. Ha. I have been interested in the Back to Eden method, he’s pretty convincing. Thank you.
edward s frotten
learn’t so much from you hands down- thank you!
I just read your article and results to putting chips on your garden. I live in Myrtle Creek, Or. and have very sticky clay soil. When it dries out in the summer, it’s as hard as cement. We tilled lots of sand and compost to it in 2007 and just compost until 2010. It was then that I heard about the Back to Eden Method and gave it a try. I was astonished how healthy the vegetables looked and tasted after one year. Wasn’t thrilled at the weed prevention, but it was better.
The soil improvement is the best part. Soft and not sticky any longer. I can actually walk in the garden without getting mud on my shoes. Still need to weed where the chips are shallow or where soil is exposed. I make my own compost and add it before a layer of chips in the Autumn. 😊
From what I understand, it is better to chop leafy tree branches for this method. The leaves would add more nitrogen than wood chips alone.
I went to the Back To Eden method so I wouldn’t have to wait until late May to till since it’s so wet in SW Washington. I found similar nitrogen results when wood chips didn’t have enough green in them when I put them down. One of the best things I did was to plant some bocking 14 comfrey (the kind that spreads by rooting, not via seed) and use the leaves in my wood chip pile. It grows incredibly fast and is great as a chop and drop green manure. I also made compost tea with the chopped up comfrey leaves, and poured the diluted comfrey tea in garden areas where nitrogen was low (for a boost). Interested to see how your long term trial goes!
Thanks for your informative site. I have learned so much. One question: Our area has earwigs that won’t quit, eating all our veggie plants even if they manage to survive to become full-sized. We’ve tried different trap methods, but they never help much. Any suggestions?
When I look at your BTE garden, I don’t see wood chips. I see sawdust. Why did you use sawdust for a BTE garden? They aren’t the same thing at all and specifically the BTE garden recommends a woody with leafy greens wood chip. I have done BTE gardening for three years now (about 2/3 of my garden has chips) and it has been wonderful for me here in Oklahoma. I appreciate your effort here except that it’s not really a true comparison of BTE vs. other methods. I am lucky enough to be able to go to the city mulch site and get all the mulch wood chips I need for free. They will even dump a big load in the back of my truck.
I was wondering the same thing. To all the people interested in this method, make sure you are not using saw dust or wood shavings. Use actual wood chips.
You never mentioned if you used conifer chips or hardwood chips. We are in the Pacific northwest and have a lot of fir. The fir will deplete the nitrogen more than a hardwood. Gardeners here get hardwood chips from us when we process hardwood. They do not want the fir because it depletes the nitrogen as you stated.
Hello. I wanted to ask you. What kind of wood should be used. Is there any kind of wood chips that could harm the soil / garden.
Thanks for any Info
Most wood chips are fine, including conifer evergreens (though you have to usually add more lime to counteract the acidity.) Don’t ever use a wood that puts out poisons to other plants…like Black Walnut, Butternut (the wood is poisonous to humans) etc. Chips or sawdust are both fine, I’ve found the sawdust breaks down faster. I get mine from a local lumbermill which usually does spruce, cedar, and hardwoods. I’ve been using both for years on what 25 years ago was pure sand. For 15-17 years I struggled, adding massive amounts of organic material, which dissolved to a few black specs here and there within a couple months. I got to where the soil looked dark but was devoid of nutrients and water holding power, baked in the summer and froze in winter. What a difference 6″ of chips and sawdust made! In one year it’s insulating temperatures (cold and too hot), holding moisture, holding nutrients most of the summer rather than completely leaching out by mid June. Now after about 7 years I only add 2-3″, and my garden grows twice the size of my most of my more accomplished gardening friends. Every year since I began 25 years ago, I do soil tests, and add the least expensive organic amendments I can find. About every 2nd or 3rd year I also add about 2-3 inches of horse or cow manure. Outrageously fab and healthy veggies, fruits, and flowers.
Do you need to let the wood chips age for awhile before putting them in the garden?
No, green is actually better because there’s more nitrogen in them at that point.
I have lots of wood chips and pine needles. You encourage me to try to use it in our veggie garden. I will try now also to use them in our very heavy clay garden. Would you recommend wood chips and pine needles for potato planting?