Got compaction? These clay-busting plants penetrate heavy soil to leave it loosened, aerated, and enriched. Jumpstart a regenerative garden ecology.
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When Mr. TAF and I bought our dream homestead, visions of gardens danced in our heads. There was only one problem: an important fix to the exterior of the house brought various crews of workers.
In the process, big trucks and heavy machinery scraped the beautiful, rich topsoil from the yard, leaving behind compacted clay subsoil. 😭
Although I’m ready to jump into gardening mode now, I can’t ignore this setback. After all, soil is the foundation of a thriving permaculture garden! The best pre-step to planting a garden is to regenerate a rich soil ecology. Clay-busting plants are essential to my plan.
The following clay-busting plants can also heal soil in existing vegetable gardens or perennial food forests!
Healing Soil with Clay-Busting Plants
On my new garden site, my goal is to punch through the compacted soil, loosening and aerating it. Next, I want to inject it with rich, organic matter that my crops will love.
To really jumpstart my new garden’s success, I also aim to build soil life and fungal networks to develop a rich, regenerative garden ecology.
The best news? Clay-busting plants can do all of this for me, no back-breaking work needed!
Interestingly, although tilling is a soil-loosening strategy, it may cause more harm than good by destroying soil structure, soil life, and fungal networks. Read more about the benefits of a no till garden.
The following list of clay-busting plants have gotten me out of a jam or two in the past!
5 Annual Clay-Busting Plants
Use the following annual plants as a cover crop in vegetable beds that need a rest or a boost. Or interplant them among crops to create compost in place.
These clay-busters can also act as soil-healing placeholders in areas slated for perennial gardens.
In fact, all of the following plants are commonly sown in the understory of food forests and fruit tree guilds. Let them self-sow to be semi-permanent wild sources of chop-and-drop mulch. It’s an easy way to generate compost in place and build soil without the labor!
While some of these plants have taproots (also called spike roots), others have dense, fibrous roots. What they all have in common is a vigorous growth habit that persists even when the going is tough.
#1: Artichoke (Cynara scolymus)
Artichokes develop deep, sturdy taproots and are a great mulch plant—both benefits to healing soil.
The taproots bust through heavy soil, and a bonus to planting them is that they’re edible!
Short-season annual varieties like Imperial Star or Colorado Red Star are quick-growing and can yield a harvest of edible flower buds from midsummer to mid-fall.
Harvest at bud stage, then chop and drop the entire plant in place to make quick mulch and build soil in place. Leave the roots to decompose.
Artichoke is related to thistle, so note that the plants are spiny. I like to wear my rose pruning gloves when handling the plants.
Would you like to learn more about improving the quality of your soil, reducing maintenance, and increasing yield?
You’ll find loads of information just like this in my award-winning book, The Suburban Micro-Farm.
#2: Daikon Radish (Raphanus sativus)
Daikon radishes might be my favorite clay-busting vegetable, plunging up to 24 inches into the soil. Also, they’re delicious!
Sow them spring, summer, or fall. Harvest some for eating around 50 days, then let the rest grow until they flower or die back. Snap or cut them off at ground level and let them rot.
These magicians break up clay and build humus as they rot. The flowers attract beneficial insects, too! Here are the seeds that I buy.
#3: Cowpea (Vigna unguiculata)
Like many legume species, cowpeas (southern peas) have vigorous, dense, fibrous roots that break up clay soil. As nitrogen fixers, they enrich and enliven the soil.
Sow in the spring as a summer cover crop. They grow quickly to suppress weeds, and the flowers attract beneficial insects.
To achieve maximum root growth and provide maximum nitrogen content to the soil, cut the plants back while flowering (before they set pods).
Can you harvest cow peas to eat? Yes, you can harvest them as you would green beans or wait until the pods dry to harvest soup beans. A benefit of planting them as a combination cover crop-vegetable crop is that the flowers become an insectary for beneficial insects.
Cowpeas are easily killed by frost when grown as a crop. Simply cut them back in the fall to allow the plant matter to decompose over the winter. Bush varieties are easier to manage.
#4: Mustard (Brassica spp.)
This precursor to our beloved Brassica crops (broccoli, cabbage, kale, etc.) can often be found growing as a weed in areas that have become compacted. That’s because it’s a superstar clay-busting plant with a massive, fibrous root system.
It’s a good reminder that nature allows the right plants to grow where they’re needed. Read more about the benefits of weeds.
Mustard is a vigorous producer of biomass, so you can grow it as a chop-and-drop green manure/mulch. In addition, it is known to suppress soil-borne pathogens.
*In the vegetable garden, cut mustard back while flowering (before it goes to seed), at least three weeks before planting a spring crop.
Timing is important for two reasons.
First, mustard disperses vigorously if allowed to go to seed. Although my home site hasn’t been pasture for 80 years, mustard still pops up along the driveway. (I don’t mind, the pollinators love it!) It was likely grown as a forage crop that escaped.
Second, mustard can have allelopathic effects on the soil while it employs its disease-suppressing action, which is the main reason for the 3-week delay before planting a crop.
Incorporate plant matter into the soil with a digging fork immediately after cutting to take advantage of its disease-suppressing benefits. Do not follow mustard with Brassica crops.
The leaves, flowers, and seed are edible, which is why many gardeners allow it to self sow in a food forest or fruit tree guild. Chickens love it, too!
#5: Annual Sunflower (Helianthus anuus)
How about a clay-busting plant that brings cheer to the garden? Sunflowers are an excellent choice for a summer cover crop.
Look for varieties that don’t need staked—they’ll establish vigorous roots deep into compacted soil. I like the variety soraya.
Sunflowers are a superb insectary, attracting hundreds of varieties of insects. They can also provide forage for chickens. And don’t forget to save a few stems for a cut flower bouquet!
In late winter, cut the plants back but leave the roots to decompose and enrich the soil. Although sunflower roots are known to have an allelopathic effect on the soil, allowing them to decompose over the winter should prevent this from being a problem for spring planting.
Are you returning an area with clay soil to nature? Read about planting native perennial sunflowers.
Tools for Clay-Busting
If you’re getting started with a bare spot of clay subsoil (like me), then a broadfork is the tool for you. Use it for hand tilling, which is more gentle than regular tilling. Beware that your first pass through the soil with this tool will be quite the workout!
Wait until the soil has dried out before getting started. If you can walk across the area without your boots getting stuck, then you’re ready to start! Work backwards over the garden area with the broadfork so as not to step on loosened soil.
Next, sow seeds of your clay-busting cover crop, water regularly, and watch the magic happen!
The Digging Fork
While I mainly use the broadfork to jumpstart soil regeneration, the digging fork is my favorite tool for long term maintenance. I use it to poke holes throughout the garden to aerate the soil every spring and fall. It’s easier to wield than the broadfork!
Soil Amendments for Clay
Among my favorites are biochar, greensand, and worm castings for enriching the soil once the clay-busting plants have loosened and aerated it. See them all (and more) in my Improving Clay Soil Amazon Shop.
Need more tips?
Get additional strategies for clay soil in these articles:
- 9 Organic Soil Amendments for Growing Vegetables
- Beware, This Manure Will Destroy Your Garden
- How to Improve Clay Soil in 6 Steps
Perennial Clay-Busting Plants for the Food Forest
Looking to prepare a site for a food forest or fruit tree guild? Or simply want to sow a soil-enriching understory? My favorite clay-busting perennials are:
You’ll notice that a few of my favorites tend to make it onto some gardeners’ list of hated weeds! Remember, these pioneering plants have the most vigorous roots to bust through clay and enrich the soil as they decompose.
If nature is left to itself, fertility increases.” ~ Masanobu Fukuoka, The One Straw Revolution: An Introduction to Natural Farming
Never underestimate nature’s ability to heal soil, fertilize, and compost in place so that you don’t have to lug around so many wheelbarrows of compost and mulch. Clay-busting plants are ready to go to work for you.
What clay-busting plants have you put to use in your garden?