How perennial plants help build soil

3 Ways Perennial Plants Help Build Soil

Building soil is a core part of cultivating abundance for people, plants and wildlife. Without healthy, rich soil, the plants (and the food web that depends on them) cannot thrive. One way to build soil is to plant perennial plants. Perennial plants help build soil in several ways. Let’s dive into those now!

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If you’re not familiar with perennial plants, these are plants that come back year after year without needing to be replanted. Some may live for a relatively short time, (3 to 5 years,) but many will live for decades.

But even short-lived perennial plants still provide benefits over annual plants, which have to be planted every year.

And perennial plants aren’t just trees and shrubs—you can also plant perennial vegetables and other non-woody perennial plants, like strawberries. This gives you a lot of options to mix perennials into your various growing areas—even your garden!

So how do perennial plants help build soil? They do it in 3 core ways:

  1. They reduce or eliminate soil disturbance.
  2. Perennial plants keep living roots in the ground at all times.
  3. They provide perennial ground cover.

A great way to get the most out of your perennial plants is to replace your annual plants with them! This means planting perennial plants in your garden. A great way to do this is to plant perennial vegetables—especially perennial greens.

These are perennial vegetables that can take the place of chard, kale, spinach, and other more traditional garden veggies. Make sure to grab your free and easy-to-print cheat-sheet, which covers 11 great perennial greens.

Perennial Plants Help Build Soil by Reducing Soil Disturbance

Perennial plants help build soil - this nodding onion is an example

These nodding onions are a wild onion that is native across much of the northern United States. While their bulbs are small, they provide great greens that are a nice substitute for onion greens. And you can use their bulbs, too.

When you plant perennial plants, you almost always end up with less soil disturbance. For one thing, you’re not going to till an area where your perennial plants are planted.

And once you’re done planting, you don’t have to dig into the soil anymore.

The result of this reduced soil disturbance is that soil life can begin to thrive. Soil life, such as fungi, earth worms, bacteria, nematodes, etc. are all a key part to healthy soil and healthy plants.

When your soil is healthy, you get predatory nematodes, which actually eat soil pests that can harm your plants. Plus other soil life, like fungi, all provide similar benefits—fungi will even transport nutrients and water to your plants.

But every time you disturb your soil, you kill some of this soil life. So when you plant perennials and stop—or at least reduce—your soil disturbance, then your soil life can start to thrive.

And your plants will thank you for it.

Because all this increase in soil life will steadily improve your soil through nutrient cycling, by controlling pests and diseases, and by increasing organic material in your soil.

This has the added benefit of increasing how much water your soil can hold, and it also makes your soil lighter and fluffier. This makes it easier for plant roots to go down deep, so they can access more nutrients and water.

Wild Tip:

You should also add mulch around your perennial plants. While you can mulch annuals, (I do this in my garden,) it’s much easier to spread mulch around mature perennial plants than small little annual seedlings. All this mulch will help feed the soil life and protect the soil from the heat of the sun and drying winds.

Perennial Plants Help Build Soil Through Their Roots

Did you know that plants release little packets of sugars and proteins into the soil through their roots? This isn’t a waste product or the plant roots “leaking”—this is a purposeful process done by the plants to help themselves grow.

So how does this work? What are the plants doing?

Those little packets of sugars and proteins are called root exudates. And they’re not food for the plant, but instead are food for soil life.

Your plants are releasing these root exudates in order to attract beneficial soil life, such as fungi and bacteria, that will in turn provide nutrients that the plants can’t normally access.

The video at the top of this section goes into this in more detail. But the key takeaway is this: your plants release upwards of 25% of all the sugars they produce into the soil around them in order to attract and feed beneficial soil life.

This soil life is key to healthy, nutritious plants. While annuals release some exudates, perennial plants are far better at supporting soil life.

Annuals don’t need to invest as much in soil life since they go through their whole life cycle in a single year. This is why in nature, annuals tend to be found in poor and degraded soils.

But perennials are going to be growing and living for years to come. It makes sense for these plants to invest in the soil through the release of root exudates.

By doing this, your perennial plants know that they will have healthy soil that will let them thrive for years to come.

The result is more abundance for you, your plants, and wildlife.

Perennial plants also don’t die in the winter, so they keep feeding soil life through their exudates throughout most of the year. And even when they go dormant in the winter, they’re still helping to hold the soil together. And come spring, they will quickly start releasing exudates again with their established root systems.

Combine perennial plants with a good mulch layer, and your soil life will thrive. The result is very happy and abundant plants!

Perennial Plants Provide Year-Round Cover

Grow Pacific waterleaf in your shady spots

While I put mulch around all my plants right now, one day I don’t want to see any mulch. I want it all to be covered up by my plants. Eventually, the plants will even replace the need for mulch.

Another way that perennial plants help build soil is simply by helping to keep it covered. While annuals can do this too, perennials are often better at it.

Evergreen perennials don’t die back in the winter, so they keep the soil covered all year round. But even perennials that do die back each winter will quickly leaf out and provide cover in early spring and likely well into the fall.

Annuals will need time to get established every spring, and it won’t be until the summer that they finally provide a full amount of cover.

This increase in cover that perennial plants provide builds soil by protecting it from rains, wind and the sun.

Winds blowing over your soil will dry it out, and sometimes even blow soil away. (This is what happened in the dustbowl.) But when you plant perennial plants, you keep the soil covered and protected from the wind.

The increase in cover also protects the soil from the sun. Without good cover, your soil can get baked in the summer.

Your plants hate this, but so does the soil life. All that soil life that your plant needs to thrive just can’t survive in hot, baked soil. But with good perennial cover, your soil will be shaded and significantly cooler.

The last way the cover provided by perennial plants help build soil is by intercepting the rain and slowing it down.

In places that get a lot of rain, like here in western Washington, all that rain can damage the soil. Hard rain on exposed soil can compact it and wash it away.

But if the soil is covered by your perennial plants, the rain first hits those leaves and then slowly reaches the soil.

This solves the problem of the rain compacting the soil.

And all those living roots will help hold the soil together and reduce any issues with the soil washing away. Essentially, your plants are providing cover both above and within the soil.

Wild Tip:

In the fall, don’t make life harder for your plants. Leave all the old stems and leaves where they fall on the ground. This will create a mulch layer that will help keep the soil covered over the winter and feed all the beneficial soil life.

Getting Started with Perennial Food Systems

Find native plants like this checker mallow

I love my perennial food plants. One of my favorites here in western WA are checkermallows. These are great easy to grow native perennial greens. Plus, they’re beautiful!

While perennial plants help build soil, this isn’t the only benefit they can provide. There are many great perennial food plants that not only help build soil, but also provide you great harvests.

Fruit and nut trees and berries are all great perennial foods. But perennial vegetables are another great option, and they can be planted right in your garden.

You can replace many traditional annual vegetables with perennials so your garden will have living roots in it all year round.

The more you can switch from annuals to perennials, the better your soil will be. Plus, it will take much less work to get abundant food harvests!

Another great option is to switch from a traditional garden to what is called a food forest. This sort of system is based around a few core fruit or nut trees, with shrubs planted around them and non-woody plants like perennial vegetables or even traditional annual vegetables mixed in.

As long as you keep your food forest open, there will be plenty of light for most vegetables.

But regardless of whether you start your own food forest or add some perennial vegetables to your garden, the result will be better soil over time. Perennial plants help build soil, and the more you can integrate perennials into your property, the better your place will be.


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Daron

Daron is a restoration ecologist, lifelong gardener, and founder of Growing with Nature. He created this site to help people enjoy wildlife, grow food, and help heal our living world. He has managed the restoration program for a local non-profit, and he’s applying principles of restoration and permaculture to transform his property in western Washington to forests, wetlands, hedgerows, food forests, and permaculture gardens. He holds a Masters in Environmental Studies and an Associate of Applied Science degree in Water Resources. He loves sharing the joy of growing food with his two beautiful children.

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