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Do you have compacted soil in your garden you’re trying to fix? Want to avoid compacting the soil in your yard or garden? This article will tell you how!
What happens when you pour water on to a solid surface like a stone countertop? What happens when you pour water over a sponge?
These two scenarios are very analogous to something that you see every day but may not notice: soil compaction.
What is soil compaction?
The simplest definition of soil compaction is the reduction of pore space in your soil.
Soil that has been heavily compacted will not be able to:
- absorb or hold water,
- cycle nutrients (e.g. maintain fertility),
- have good seed germination rates,
- provide sufficient oxygen to grow plants or allow plant roots to penetrate,
- have a flourishing soil food web or high microbiological activity necessary to feed and protect plants from pathogens.
Compacted soil is dead soil (or at least soil that’s on life support) that will not grow healthy plants. The good news? You can take steps to both prevent soil compaction as well as steps to bring heavily compacted soil back into good health.
5 Ways to Prevent Soil Compaction From Happening In Your Garden
1. Don’t stand or walk in your garden beds.
We see many new gardeners and garden visitors breaking this rule, so it bears repeating: do NOT stand or walk in your garden beds where you intend to grow plants!
If you do this on a regular basis, you’ll compact the soil.
2. Install garden paths and/or stepping stones.
What do you do if you need to walk around in your garden or step into certain spots to harvest? Install walking paths or stepping stones.
Stepping stones do mildly compact the soil, but they work like snowshoes, distributing your weight over a broader surface area. If you’ve ever turned over a large stone in your garden, you’ll also notice that they provide great habitat for worms, beetles, and other critters that serve to aerate your soil for you.
Stepping stones also provide a visual reminder to you and others that “this is where you should step.”
3. Make the width of your garden beds no wider than twice your arm length.
As a general rule, don’t make your beds wider than 4 feet if you have a walking path on either side of the bed. This allows you to easily reach the middle of the bed from either side without having to step into the bed.
If there’s only a walking path on one side of the bed, only make the bed the width of your arm.
4. Use raised beds or fencing if/when necessary.
If you have children, large pets, or a high-trafficked yard where you also want to garden, it probably makes sense to install either fencing or raised beds or both.
Here’s a list of our top recommendations of quality raised garden beds you can quickly assemble that won’t cost you a fortune.
5. Feed your soil, don’t till it.
We haven’t tilled our soil in a decade, and we started with heavily compacted red clay in our garden. Despite conventional wisdom, tilling your soil is unnecessary and it’s actually quite harmful to the trillions of living organisms that make soil healthy.
Instead of tilling your soil, feed it with mulches, composts, and living plant roots. Mulches can include shredded leaves, wood chips, and cover crops.
Then, let nature/biology do all the work for you. Click here if you want to read more about the how’s and why’s of no-till organic gardening.
3 Ways to Fix Compacted Soil in Your Garden
Are you trying to figure out what to do with soil that’s already heavily compacted? The good news is you can regenerate healthy soil very quickly and with surprisingly little work.
We’ve read piles of research on this topic and put that knowledge to work on heavily compacted red clay soil in our own yard.
Here are three ways to fix heavily compacted soil in your yard/garden, depending on whether you want to take a slower, less work-intensive way or get your soil fixed now:
1. Slow way to fix compacted soil – about 1 year
Pile organic matter 12-18″ deep on your soil surface. Organic matter can be any of the following (or combinations of the following):
- wood chips
- chopped leaves and yard clippings
- straw or pine straw
Assuming you live in an environment that gets heavy rain several times per month, this organic matter will slowly decompose and come alive with worms and other soil organisms. After a *year or less, all of (or at least the vast majority of) the organic matter will have decomposed, becoming rich, garden-ready soil in the process.
*Keep in mind that:
- Lighter, less carbon-dense materials (ex: pine straw) will decompose faster and provide less final soil depth than heavier, carbon-dense materials like wood chips. 12″ of wood chips might result in 6″ of topsoil, whereas 12″ of straw might result in 1-2″ of topsoil.
- Organic materials will decompose faster in warmer, wetter environments than in cooler or dryer environments.
One the organic matter you’ll placed on your compacted beds has been converted into soil, it’s time to put plants in the ground!
2. Medium length way to fix compacted soil – about 1 month
Macro and microorganisms in soil are what naturally build and maintain healthy, living soil. When soil is compacted, those organisms can’t penetrate, move around, or find plant roots to symbiotically interact with.
How can you quickly regenerate the health of previously compacted soil in your garden? First, till the surface or break it up with a shovel. Next, spread 2-6″ of high quality worm castings or compost on the surface. Finally, cover the castings/compost with 3-6″ of mulch.
Make sure the area gets 1″ or more of water per week. Your beds will be ready to plant within a month. Just pull back the mulch by hand wherever you intend to sow seeds or put in transplants. Of course, continuing to add worm castings, compost, and mulch 1-2 times per year will continue to improve the health and depth of your living garden soil, so don’t stop going!
3. Fast way to fix compacted garden soil- 1 day
Do you have highly compacted soil but want to be able to “fix it” and put in seedlings or sow seeds the same day? If you’re more of a hare than a tortoise, no worries. You’re going to do pretty much the same thing as in #2, but with a few modifications.
First, till or break up the top of the compacted soil (using a tiller or a a shovel. Add worm castings or compost, but apply them more deeply: 6″ thick or more.
Next, put in your seeds or seedlings, and instead of top-dressing the beds with 3-6″ of mulch, put down a thinner mulch layer about 1-2″ thick. Straw or pine straw works great here since a light layer won’t block out germinating seeds. If you want to use a heavier mulch like wood chips, taper them off wherever you’ve planted seeds so you don’t block the germinating seeds from reaching the surface.
The compost/worm castings will provide your new seedlings with the bio-available nutrition they need while the microbes and plant roots start to bring life back into the previously compacted soil.
Regardless of which approach you take to preventing or fixing compacted garden soil, the aim is to let biology do the bulk of the work for you.
If you want to really geek out on understanding how soil works and how farmers are using similar methods to regenerate healthy soil on large acreage, we strongly encourage you to watch this presentation by one of our heroes, soil microbiologist Dr. Elaine Ingham.