When it comes to naturally creating a weed barrier and improving soil health, cardboard might be your garden’s most underrated tool.
Uriah Israel walks us through the concept of sheet mulching—a regenerative gardening method that uses cardboard as a biodegradable weed barrier. It’s not only affordable, but it’s effective, simple, and soil-friendly.
What Is Sheet Mulching?
Sheet mulching is the practice of laying down cardboard or similar biodegradable materials in your garden beds to suppress weed growth. The cardboard serves as a smother layer, blocking light and preventing weeds from sprouting. Over time, this layer decomposes—usually within 6 to 12 months—depending on your soil, insect activity, and moisture level.
This method is particularly useful in no-till gardens, helping to create fertile ground without turning or disturbing the soil.
Step-by-Step: How to Use Cardboard as a Weed Barrier
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Choose Your Cardboard
Use corrugated or standard cardboard. Remove any tape or labels. Avoid glossy or printed materials. -
Soak It Thoroughly
Moisture activates the breakdown process and ensures the sheet molds closely to the soil surface. Don’t skip this step. -
Add Mulch Layers
After laying the cardboard, apply a layer of natural mulch. This could be:-
Shredded leaves
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Pine straw
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Fine wood shavings (avoid large wood chips in beds)
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Top It Off with Soil
Finish by adding your topsoil. This layering creates a structured, nutrient-rich foundation.
Why Cardboard Instead of Plastic?
Plastic weed barriers may seem appealing for their durability, but they come with serious downsides:
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They don’t decompose.
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They limit water flow and air exchange.
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They can damage the soil biome over time.
Cardboard, in contrast, breaks down into the soil, contributing to organic matter and improving long-term soil health.
Final Takeaway
If you’re looking for a low-cost, no-till, regenerative strategy for weed control, cardboard sheet mulching checks all the boxes. It’s easy, effective, and supports soil life—making it a go-to method for small-scale growers and urban gardeners alike.
Start where you are. Use what you have. Let the soil work for you.
