Not all compost is created equal—and your garden knows it. In today’s gardening world, “compost” is often used as a catch-all term for anything dark, crumbly, and sold in a bag. But don’t be fooled. Compost quality varies wildly—and using the wrong kind can quietly undermine your garden’s health and productivity.
At Deep Roots Project, our innovative Transformative Gardening method is built on a simple truth: your soil is only as good as the microbial life within it. And the microbial life depends entirely on the quality of compost you use.
While many people assume compost is just “compost,” the truth is, there’s a world of difference in how it’s made and what it does for your plants. Some composts are simply a dumping ground for waste, left to rot with no real recipe or care. Others are expertly crafted with precision—specific ingredients, the right balance of moisture, temperature, and timing—to create compost that’s teeming with nutrients and living microbes. At Deep Roots Project, we know that high-quality compost can make or break a food garden. That’s why we use manure-based thermophilic compost, carefully made with heat-generating microbes that transform raw plant waste and manure into living soil gold bursting with nutrients and microbes. The farms use large machines to tum the piles that brings oxygen to the process.
Microbial Powerhouse in Deep Roots Compost
Our 100% microbe- and nutrient-rich compost is not just soil—it is the growing medium. Instead of filling beds with conventional “topsoil” or store-bought potting mixes that often lack life, we fill our raised beds with compost made through a thermophilic (heat) process using only organic matter from plants and manure from herbivores. This heat process destroys weed seeds and harmful pathogens while nurturing beneficial microbes and fungi. These living organisms then create an underground ecosystem that feeds your plants naturally, reducing the need for synthetic fertilizers.
When we add organic worm castings (vermicompost), our microbial populations explode with diversity and strength, increasing nutrient availability and plant resilience even further.
In contrast, many bagged retail composts are mostly ground-up wood chips and tree bark—byproducts of the lumber industry. These materials are low in nutrients, often still decomposing (which robs nitrogen from your plants), and nearly devoid of microbial life. Yet, they’re marketed as “organic” simply because they come from trees.
There are six common types of compost
They range from casual backyard piles to composts designed for maximum harvests. Watch out for leaf mulch since It looks like compost, but it’s not. Leaf mulch is great for native plants, shrubs, trees, and flowers —but it’s low in nutrients and shouldn’t go in your veggie beds. Ready to dig in? Let’s break down the dirty details.
• Manure-based thermophilic compost is made from animal manure and chopped up plant waste. Deep Roots uses this 100% compost instead of traditional soil to fill new raised beds, and to replenish nutrients in existing beds at the beginning of every growing season.
• Spent mushroom thermophilic compost is the leftover growing medium from mushroom farms made from manure and plant materials.
• Premium thermophilic compost is same as manure-based compost, plus it contains extra boosts like seaweed and fish protein.
• Municipal facility compost is mixed waste from homes and restaurants. There are no uniform regulations nationwide, though there are somecommon standards and best practices. It is not recommended for food gardens unless quality is verified.The exact inputs, processes, and end-product quality can vary significantly. Never use if contains biosolids (sewer sludge).
• Backyard compost is miscellaneous kitchen and yard waste naturally decomposed without heat (called “cold composting”). It is low quality, suitable to supplement any soil. Not recommended for growing food.
• Vermicompost (also called “worm castings”) is worm poop that has been processed by red wiggler worms (Eisenia foetida). Vermicompost is supercharged with microbial activity and plant-boosting compounds that help gardens truly thrive.
A Warning About Toxic “Composts”
Perhaps the most dangerous composts are those made from sewage sludge, commonly marketed under green-sounding names like “biosolids” or “recycled waste.” These materials come from municipal wastewater treatment plants and contain far more than just human waste.
Sewage sludge can include:
• Heavy metals (lead, mercury, arsenic, cadmium)
• PFAS (“forever chemicals”) linked to cancers and hormonal disruption
• Pharmaceuticals and hormones (from medications flushed down the drain)
• Microplastics
• Pathogens like E. coli and Salmonella
Though these biosolid products are legal to sell in many areas, they pose serious risks to human health, soil microbiomes, food safety, and local water supplies.
That’s why Deep Roots will never use biosolids, and we encourage you to avoid them, too. Always ask what’s in your compost.
What About Free Municipal Compost?
We understand that buying premium compost isn’t always in everyone’s budget. Some gardeners rely on free municipal compost, which is typically made from leaves, grass, and brush. This compost isn’t harmful, but it’s usually low in both nutrients and microbial life compared to Deep Roots compost.
Here’s a great solution: You can safely use municipal compost if you mix in our top-quality worm castings. This combination boosts microbial activity and improves nutrient availability. While not as effective as using 100% Deep Roots compost, it’s a strong compromise when budgets are tight.
Why Deep Roots Compost Is Worth It
Compared to most retail options, our compost is:
• More nutrient dense
• More microbially active
• Free from toxic materials
• OMRI and USCC certified for organic food growing
Yes, Deep Roots compost may cost a little more. But it’s a small investment that pays off in healthier plants, bigger harvests, and safer soil.
Bottom Line: Not All Compost Is Equal.
Your garden—and your health—deserve better than compost made from industrial waste or bark chips. Choose compost that supports soil life, not destroys it.
Choose Deep Roots Compost.
Join the Deep Roots movement
We’re not just about gardening; we’re about changing the way people grow food. Whether you have a tiny balcony or a full backyard, we’ll help you grow like a pro.
Stay in the loop: Signup for our email newsletter. If you also provide your phone number you will get text message updates that link to our best blog posts.
Get involved: Attend a free workshop, become a volunteer, grab a raised bed, or simply follow along for expert tips. Contact our support team any time you have a question at 708-655-5299 and support@deep-roots-project.org.
Learn. Share. Grow. Volunteer: We invite you to be a part of our sustainable movement right here in our own backyards! We want all our volunteers to have fun and learn while they contribute to expanding the Deep Roots community. We can customize a volunteer assignment to your time, interests and skills. Learn more on our Volunteer page
Let’s make this your most delicious year yet!
Dive Deeper
Click on the Blog Posts Below for more about our Innovative methods.
Beautify Garden with Our Cedar Raised Beds!
Our Deep Roots handcrafted cedar raised beds are designed to endure outdoors while adding a touch of style to your yard. As a bonus, they are the perfect depth to hold just the right amount of our nutrient-rich compost growing medium, which comes free with each bed.
Deep Roots Supports Gardeners
We provide our gardeners with the best products for success – like cedar raised beds, microbe-rich compost and microbe-rich worm castings. Check our online store. Always talk to our customer support team before placing your order online. If you need help or have a question contact us at support[at]deep-roots-project.org and 708-655-5299.
Deep Roots Online Store
See our online store for details about prices, ordering and delivery of raised beds, planter boxes, microbe-rich compost, worm castings, leaf mulch and more. We don’t sell traditional soil, since we use 100% compost as our growing medium. Our online store has 2 sections – (1) raised beds and planter boxes and (2) compost, worm castings, fertilizer.
Please contact our customer support team before placing an order online so we can assist you with the details and answer your gardening questions. You can pay by credit card in the store or by check.
Please leave your cell phone number when you sign up for our eNewsletter, if you want text message announcements now and then.
Donations help us provide organic kitchen gardening education to individuals, organizations, and entire communities. Thank you in advance for contributing to our community and for sharing our website and blog with friends and family.
