For over 20 years, I’ve experienced both spectacular successes and total failures in my life as a gardener. That’s because gardening comes with its fair share of misconceptions, especially when we’re talking about soil management. Understanding the truth behind these myths makes the difference between a healthy plot teeming with life and one that struggles to produce.
Let’s look at 10 common myths about garden soil and debunk them with science-backed explanations and practical insights. Whether you grow in the ground or in raised garden beds, your plants will benefit from healthy, living soil.
Myth #1: Garden soil needs to be tilled every year.
Regularly tilling your garden can destroy soil structure and nutrients over time. Tilling, once considered essential, is now recognized as harmful to soil health. Not only can tilling disrupt the natural structure of the soil, it can also destroy beneficial soil organisms such as earthworms and mycorrhizal fungi. These little helpers play a key role in aerating the soil, breaking down organic matter, and making nutrients available to plant roots. Frequent tilling can also increase erosion by loosening the topsoil, making it more susceptible to the effects of rain and wind. And let’s not forget that tilling on a larger scale releases carbon into the atmosphere.
In contrast, no-till gardening practices preserve soil structure and promote a healthy ecosystem. By leaving the soil undisturbed, organic matter accumulates on the surface, enhancing soil fertility and moisture retention. Instead of tilling, use cover crops, mulch, and compost to enrich the soil naturally, control weeds, and reduce the need for chemical fertilizers. Adopting no-till or reduced-till practices leads to healthier soil, more sustainable gardening, and less work in the long run.
Related: Raised Row Gardening–The Best ‘No-Till’ Method
Myth #2: All soil amendments work for every type of soil.
If only! While helpful for gardeners, soil amendments are not a one-size-fits-all solution. That’s because different soils have different needs. While acidic soils might need lime to raise the pH, making nutrients more available to plants, alkaline soils might benefit from sulfur or organic mulches to lower the pH. Understanding your soil through soil testing is crucial before choosing amendments.
One thing that is helpful to almost all soils is organic matter–but for different reasons. For instance, clay soils tend to be dense and poorly drained. Adding compost or well-rotted manure improves clay soil by increasing its porosity, enhancing drainage and providing a better environment for root growth. Sandy soils, on the other hand, struggle to retain moisture and nutrients. Adding organic matter to sand helps improve moisture retention and nutrient holding capacity, making compost or coconut coir particularly beneficial.
Myth #3: Adding sand to clay soil improves drainage.
Adding sand to clay soil often leads to more problems than it solves. When sand is mixed with clay in the wrong proportions, it can create a concrete texture, further compacting the soil and worsening drainage issues. So what should you do instead?
A more effective solution is to add (you guessed it) organic matter, such as compost, leaf mold, or well-rotted manure. This will improve your soil’s structure by enhancing porosity and providing a habitat for beneficial soil organisms. Mulching clay soil further increases organic matter and protects the soil from compaction. Adding organic matter over time will transform heavy clay into a more friable, productive soil.
Related: Know Your Soil Type–How to Make the Most of Your Garden Soil
Myth #4: Fertilizers can replace the need for good soil.
Fertilizers are often seen as a quick fix, but they can’t replace healthy soil. While fertilizers provide the nutrients that plants need for growth, they don’t support good soil structure, water retention, or the diverse community of microorganisms needed for long-term soil health. Good soil is more than just a carrier for nutrients. It’s a dynamic ecosystem.
While chemical fertilizers might show results in the short term, healthy soil creates the perfect environment for plant roots that will support growth over a plant’s entire lifespan. Over-reliance on chemical fertilizers can degrade soil over time, since these fertilizerrs may disrupt microbes or cause nutrient imbalances or salt buildup. While fertilizers can supplement soil nutrients, they should be used along with practices that build and maintain healthy soil, such as adding compost, mulching, and practicing crop rotation. Organic fertilizers, which are slower acting, are more compatible with this holistic cycle.
Myth #5: Garden soil should be sterile to prevent disease.
Not so! While it’s true that pathogens can exist in the soil, sterilization eliminates beneficial microorganisms that are essential for plant health. These microbes, including bacteria, fungi, and beneficial nematodes, play important roles in breaking down organic matter and protecting plants from harmful pathogens.
Sterile soil lacks microbial diversity and can lead to an increased susceptibility to diseases over time. When I interviewed a commercial cut flower grower earlier this year, I learned she doesn’t even use sterile potting mix for her seedlings.
Plants grown in sterile soil are often more vulnerable to pathogens because they lack the natural defenses that a healthy soil microbiome provides. Instead of sterilizing soil, promoting a healthy soil ecosystem is a more effective strategy. Achieve this by adding organic matter, using microbial inoculants, and practicing crop rotation and companion planting to maintain soil health.
Myth #6: Compost can be used as a complete replacement for soil.
While compost is our favorite amendment to create healthy soil, compost lacks the structural stability that soil provides. Soil is a complex mixture of minerals, organic matter, air, and water, each component playing a vital role in supporting plant growth. Compost is much less dense than soil and can result in poor anchorage for plants, making them more susceptible to wind and other disturbances. And, while compost provides many essential nutrients, it can compact over time. In addition, compost alone can hold too much moisture or dry out too quickly, depending on its composition. To achieve the best results, mix compost with existing soil to create a balanced growing medium.
Myth #7: The more fertilizer, the better the plant’s growth.
Unfortunately, no. Over-fertilizing can harm plants and the environment. While fertilizers provide essential nutrients for plant growth, too much can lead to nutrient burn, where high concentrations of salts from the fertilizers damage plant roots. Over-fertilization can also cause nutrient imbalances, making it difficult for plants to absorb other necessary nutrients.
Not only that, excessive use of fertilizers has serious consequences for the environment. Runoff from over-fertilized gardens can contaminate local waterways. While this is more common with large-scale agriculture, even small areas may become contaminated if the inputs are dense enough. To promote healthy plant growth, use organic fertilizers and apply them judiciously, based on soil tests.
Related: The Best Organic Fertilizers to Double Your Harvest
Myth #8: Garden soil should always be loose and fluffy.
Loose and fluffy soil is great for germinating seeds and growing new roots, but overly loose soil can collapse and compact as it settles, leading to poor aeration and drainage. This can create an unstable environment for plant roots, making it difficult for plants to establish a strong root system. Soil needs some structure to support plants and maintain good air and water movement.
Good soil structure includes a balance of different particle sizes that provide stability while allowing roots to access nutrients and water. Adding compost to your soil helps achieve this balance by improving texture and promoting the formation of soil aggregates.
Myth #9: Topsoil is all you need for a healthy garden.
We definitely learned this myth the hard way. Topsoil varies widely in quality and composition, depending on where it comes from. In many cases, topsoil alone lacks the nutrients and organic matter needed to support healthy plant growth. So what should you do if you need soil to fill raised beds or other growing spaces?
Since topsoil is generally inexpensive, you may choose to use it along with compost, aged manure or organic fertilizers. These amendments help enrich the soil, improve structure, and promote beneficial microbes. Soil testing can also help identify deficiencies in your topsoil and provide you with the information you need to address them.
Myth #10: Soil tests are only for professional growers.
If you could head off future headaches and save money by taking one simple step, would you? Soil testing is the key to successful gardening, providing a window into your soil’s composition and fertility. Soil tests analyze essential factors such as pH levels, nutrient content, organic matter, and soil texture, which all play significant roles in your plants’ growth and health.
By understanding your soil, you can tailor your approach to soil management, selecting the best amendments to address imbalances. This approach not only ensures the best possible conditions for your plants but also helps avoid overusing fertilizers and other amendments, saving you money. Think of soil tests as empowerment for gardeners. They don’t cost much, but they make a world of difference.
Healthy soil, healthy plants
Embracing practices like no-till gardening, composting, and soil testing will help your create the best growing conditions for your plants. By nurturing a healthy soil ecosystem, you can get the plant growth you want while minimizing environmental impact.
