How to Deal with Compacted Soil (without digging)
Dealing with compacted soil is a pain—often a literal pain, if you try to dig through it. But there is a way to deal with compacted soil without digging. When you work with plants and soil life, you can turn compacted soil into healthy soil. Let’s dive into how to do this.
One of my food forests is in an area that used to be used as a parking lot. While it wasn’t paved, it was covered with gravel, and it was so compacted that I couldn’t get a shovel into it.
I could barely even pound t-posts into it.
But today there are fruit trees, nuts and berries all growing in it. And it’s easy to dig into it with a shovel or even a trowel.
All of this was achieved in just a couple years without digging or tilling. Instead I used a combination of techniques, starting with mulch to promote soil life, and then a mix of plants to continue improving the soil.
And while this food forest is still young, the transformation is still amazing. Plants and soil life were key to this transformation of the space from a parking lot to a food forest.
Let’s dive into how you can get started with this way to deal with compacted soil without digging.
But before we do, if you want to dive deeper into food forests, here is a free and easy-to-print cheat-sheet all about getting started with your own food forest. This cheat-sheet also covers 2 fruit tree guilds that you can use as a foundation for your food forest.
Step 1 to Deal with Compacted Soil Without Digging – Promote Soil Life
If you’re going to deal with compacted soil without digging, the key is to bring in some help. But not the 2-legged variety.
What you need is soil life—literally billions of microbes, fungi and worms that all work 24/7 to continually loosen up the soil.
While this action can seem small compared to what a shovel or tiller can achieve, you’ve got to remember that this soil life will keep working constantly.
And they will work from the surface down through the topsoil and subsoil layers.
But if you’ve got compacted soil, then you’re likely lacking in soil life. So the first thing you need to do is promote and support soil life.
And if you’ve got a bunch of grass or other plants you don’t want anymore, just add a layer of cardboard first before you add the organic material. This is called sheet-mulching, and it’s a great way to prepare an area for planting.
Now you just need to wait and let the soil life do its job.
This doesn’t happen overnight. Remember that old parking area I turned into a food forest? I used this method to start the transformation of this area.
But I had to let it sit for a whole year—from one fall to the next.
I didn’t plant anything during that time. Remember, the soil was so compacted that I couldn’t even pound t-posts into it. Planting really wasn’t an option. But covering it all with cardboard and a ton of fall leaves was.
And after a year, the results really were amazing.
I was able to take a shovel and dig holes quickly and easily for fruit and nut trees, along with some shrubs.
What happened is that all that organic material I added was worked into the soil by those billions of little helpers—the microbes, fungi and worms, along with others.
And that layer of organic material provided some other benefits too:
- It kept the soil moist and cool through the summer.
- It kept the soil from freezing in the winter.
This meant that the soil life was able to keep doing their job without stopping for the entire year. Without that layer of organic material (also called mulch) the soil would have dried out in the summer or frozen during cold snaps in the winter.
Soil life goes dormant or dies back when that happens.
The result was that within a year, the cardboard was completely broken down and the leaves had mostly broken down. And of course, I could dig into the soil.
Depending on your site conditions and climate, it may take more or less time for you to get the same results. But the general process and benefits are the same regardless.
Now let’s look at the next step to deal with compacted soil without digging by planting plants.
Step 2 to Deal with Compacted Soil Without Digging – Planting Perennial Plants
Once the soil has loosened up a bit through the action of soil life, the next step is to start planting into it. And there are a couple different approaches you can take.
Here in western Washington I’ve had great luck with our native riverbank lupine (Lupinus rivularis). It easily germinates through a layer of mulch and produces very large taproots.
Including native plants during this phase can provide incredible benefits. Since native plants have co-evolved with other plants, wildlife and soil life that live in your area, they support a broader range of life than non-native plants will. This is a big reason why I use riverbank lupine.
I often chop-and-drop the riverbank lupines growing in my food forests in the spring to create a nice layer of mulch before I let them grow and flower.
Broadcast seeding is a great way to cover a large area with plants, so their roots can start working with soil life to break up compacted soil.
But you can also skip the broadcast seeding and start planting specific plants, such as trees and shrubs. Though I would still try to mix in a bunch of fast-growing, non-woody perennial plants—ideally ones like lupines that get taproots and/or fix nitrogen. This will speed up the breakdown process.
Okay. While I’m sure you don’t have an issue with planting plants, you might be wondering how these plants will help you deal with compacted soil without digging.
It all comes back to promoting soil life.
All those plants will send their roots down deep into the soil. This is especially true for taproot plants. These plants send their root straight down deep into the soil and can even punch through compacted layers.
While not a perennial plant you can try growing daikon or tillage radishes. These radishes can grow large roots up to several feet (~1 meter) deep. If you leave them in the ground to rot after a killing frost they can be a great way to add organic material deep into the soil.
The roots are likely to follow little tunnels and paths through the soil created by soil life. But it works in reverse too—soil life and water will follow the roots, too.
And plants release little packets of sugars and proteins into the soil that soil life eat. This can greatly expand the depth that soil life can survive and thrive.
Then, as the soil life starts growing in the subsoil layers, they loosen up that deep soil, allowing plant roots to go down even deeper. This, in turn, lets the soil life go deeper, too.
This cycle can repeat steadily until your plant roots can start reaching depths of 10 feet, 20 feet, or even 40+ feet (3 to 12.2+ meters) in some cases.
It really is amazing what soil life and plants can do together when given the chance.
Building Healthy Soil Takes Time – But Every Year is Better Than the Last
If you want to deal with compacted soil without digging, the 2-steps outlined here are a great path forward.
By promoting soil life and then planting perennial plants once the soil has loosened up a bit, you can make a huge difference and transform your property.
But this does take time. You’ve got to work on nature’s timeframe.
It may seem easier and faster to just grab a tiller or a shovel. But if you do this, you will be killing soil life instead of promoting it. The soil may be loosened up, but only to the depth you dig or till.
The exception is if you do the tilling or digging only once to help prepare the soil. This approach can work and can speed up the process. But make sure to follow up by adding organic material to the surface of the soil and start planting perennial plants—and then stop digging/tilling.
And tilling can result in a compacted layer right below the depth of the tiller.
But if you work with soil life and perennial plants, you can instead create a situation where the healthy soil extends deeper year after year. This, in turn, means your plants will do better each year.
It may be a bit slower at first. But over time, the results are well worth it. And you will be much better off than if you tilled or dug year after year.
Promoting soil life and planting perennial plants will not only help you deal with compacted soil without digging, but also help you to build healthy soil.
Building healthy soil is a true pathway to abundance for people, plants and wildlife.
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