We kicked off 2024 with an excellent talk by self-proclaimed nature nerd Russ Henry, owner of Minnehaha Falls Landscaping. Russ was knowledgeable, approachable, and helped our club dig into the details of why healthy soil matters, what makes healthy soil, and what destroys healthy soil. While we don’t have a recording available, the following is a summary of some key points of his talk, along with a few additional links and resources.
Why does soil matter?
As Russ put it, we can’t live without soil. Far beyond the already crucial role of being a growing medium for plants, soil also cools and cleans water of pollution before it enters our waterways, it recycles organic matter and waste, and it supports animal health. In fact, 80% of all MN native bees nest in the ground, including the Rusty Patched Bumblebee (our state bee).
When it rains, water runs over all sorts of non-permeable surfaces like asphalt, concrete, or even badly compacted soils. Because the water can’t permeate these surfaces, it just keeps moving, picking up things like pesticides, herbicides, pet waste and salts along the way. Helping direct this water run-off to soil helps in a few ways: it slows the flow of water down, it cools the water, and it cleans the water of waste products. This intervention can help prevent flooding and helps prevent excess nutrients making their way to rivers and lakes.
Why does controlling nutrients matter? Because while nutrients in water are to be expected, excess nutrients can lead to algae blooms and encourage the growth of other “nuisance” or invasive plants, further reducing dissolved oxygen levels in the water which can lead to the death of aquatic life and the break down of delicate ecosystems. These excess nutrients can also make their way into a community’s drinking water.
Critically, soil can also play a role in carbon sequestration.
So soil helps filter water in a useful way: but why is healthy soil better than un-healthy soil for managing water run-off? Because each 1% increase in soil organic matter helps soil hold 20,000 gallons more water per acre. According to Russ, at least 3.5% organic matter in the soil is required for optimal health.
What is healthy soil?
Soil is a dynamic living aggregate comprised of dirt, living organisms, organic matter, and other abiotic factors.
“Land, then, is not merely soil; it is a fountain of energy flowing through a circuit of soils, plants and animals.”
– Aldo Leopold
At the microscopic level, one big difference you’ll see between healthy soil and unhealthy soil is whether or not there is room to breathe. Healthy soil is aerobic (meaning it has enough oxygen), which is possible because roots and soil fauna create deep channels allowing percolation (the ability for water to move around the particles). In contrast, unhealthy soil collapses: it is easily compacted which leads to anaerobic soil conditions (not enough oxygen), and there’s no room to move so water can’t effectively pass through the soil. This leads to run-off and erosion: if the water could effectively infiltrate the soil, it wouldn’t skim the top surface, eroding the top layer.
In a single teaspoon of healthy soil, you can find more than 8 billion microorganisms (as many people as there are on this planet). The soil below us is dense with life and a rich, complex structure of roots and symbiotic fungi known as mycorrhizae, working together to communicate and exchange sugars and other nutrients.
If you’d like to dig in deeper on the science of this topic, check out this masterclass from Dr. Elaine Ingham (a soil scientist Russ mentioned several times).
What has caused soil destruction in MN?
According to Russ the 4 major forces of soil destruction in MN have been corn, soy, lawn and pavement. Two key contributors to soil collapse were pesticides and salt contamination (used in winter ice management).
Pesticides and herbicides create a destructive spiral: they kill soil microorganisms (along with whatever you intended to kill), this leads to soil collapse which leads to slow or no water infiltration, which increases run-off (carrying those pesticides and herbicides to the waterways). This diminished soil now leads to more weeds and more grubs (unchecked by beneficial nematodes) which tends to encourage further spraying of pesticides and herbicides. If you find your home garden caught in this cycle, more spraying is not the answer! Shift your focus to improving your soil health through the addition of organic material.
Russ also called out how the destruction of Native American land-management practices in Minnesota interrupted the effective cycle of buffalo grazing and controlled burns which helped our native plants to flourish. He made an excellent point in regards to managing invasive plants as well, pointing out that removing buckthorn and other invasive plants (without restoring native plants in their place) simply causes further erosion and collapse. As Russ put it, when speaking about invasive plants: “We can’t just say ‘darn these plants!’, we have to look back and ask what have we done to create this vacuum?”
What can we do to help?
In a talk full of fascinating science and explorations of the natural world, Russ brought his talk home with a few key bits of guidance for those of us looking to contribute to improved soil health at home:
- Keep the soil covered: use wood mulch between plants when starting a garden, and use ground covers, cover crops, and multiple layers of perennials as a living mulch.
- Minimize disturbance: No need to till as this will only destroy soil structure, avoid the use of pesticides or fertilizers (even organic, water-soluble ones), and avoid introducing plastic such as Landscape Fabric. Stick to top-dressing with lots of compost!
- Keep living roots in the soil: growing a diversity of plant species (especially native plants) with multiple layers of canopy will help enrich the soil food web and prevent compaction.
A few additional tips:
- When you go to plant in the spring: turn in 6 inches of compost to the bed, plant for diversity, and plant native where you can.
- Never mow shorter than 3 inches using a sharp blade, and consider using a bee lawn mix for a more healthy and beneficial lawn.
- Consider aeration every year around Labor Day (only do this when the soil is dry: if you aerate while the soil is wet this will only lead to compaction). Also note: aeration is different than tilling. Simply put, aeration creates holes in the ground allowing water to penetrate otherwise compacted soils, while tilling tears up the entire top layer of soil and destroys the microbial health of the area.
- If you want to over-seed, you can do this in the spring and/or fall (ideally with a bee lawn mix!)
- Leave the leaves: fall leaves provide excellent mulch and much needed nutrition for your soil. Don’t break the cycle of nutrients: let your leaves decompose directly on your garden beds. Some caterpillars also use leaves to hibernate over winter, so don’t be in a rush to remove them in spring! Give your neighbors a chance to move out first.
When life gives you dandelions, make dandelion wine
The meeting closed with an noteworthy discussion of dandelions, a flower that can cause many homeowners some embarrassment. Russ was empathetic, acknowledging the social pressure to maintain what some consider a “healthy-looking lawn” (a lawn with no visible ‘weeds’, traditionally maintained with pesticides and herbicides) as opposed to a scientifically healthy lawn (one rich in organic matter, bio-diversity, native plants, bee-friendly ground cover and yes, likely the occasional dandelion).
Russ pointed out that the root of the word ‘dandelion’ is dent de lion (French for “lion’s tooth”), and encouraged those struggling with social pressure to embrace the courage of the lion: given the enormity of the climate crisis we are facing, take the opportunity to educate those who question the aesthetic value of a plant with some insight into the rich value a plant has outside of human aesthetics and trends. Embrace the complexity of your home ecosystem and if you really want to crowd them out, consider planting some native plants as competition. And don’t forget: there’s always the option to keep your numbers low by foraging them or making some dandelion wine!
Plants mentioned
Ground covers: Prairie Pussytoes, wild ginger, blue violets, columbine, goldenrod, asters.
Bee Lawn: dutch white clover, self-heal, fescue, thyme, yarrow.
Hummingbird Friendly: Scarlet dropmore honeysuckle, lobelia cardinalis (Cardinal flower), salvia coccinea (Scarlet Sage). Look for organic seed sources for these as hummingbirds are quite sensitive!
Food Forest: Currants, nanking cherry, honey berry.
Keystone Tree: native willows are home for 350+ moths and butterflies.
Thanks again to our speaker, Russ Henry
Russ Henry is the owner of Minnehaha Falls Landscaping. Minnehaha Falls Landscaping has guided and performed organic habitat transition in hundreds of home landscapes as well as schools, parks, churches, condos, and offices. His practices are rooted in healthy soil: growing thick and healthy lawns, bee lawns, and landscapes without the use of any synthetic fertilizers, pesticides, or herbicides.
Russ is an advocate and inventor. His work has helped change Minnesota state composting laws, sprouted the statewide solar-pollinator program that has been adopted in 23 states, increased healthy food access throughout the Twin Cities, and won him several awards for garden design as well as a patent for a compost extract brewer.
Author of the book Healthy Home Landscapes, Russ helped the state of Minnesota launch the Bee Lawn program, a lawn care program that can protect bees and save land owners thousands of dollars per year.
Golden Valley Garden Club 