Sheet Mulching: A Garden Hack For Healthy Soil

The journey to a thriving garden doesn't necessarily have to be a grueling task—it can be as simple as layering your way to greatness with sheet mulching. 

 Sheet mulching is a no-till garden technique that mimics natural decomposition and soil building of the forest floor. It has emerged in the last couple decades as a popular and effective method for soil health and fertility. This technique, also known as sheet composting or "lasagna gardening," involves layering various organic materials to create a nutrient-rich environment for plants. Let's delve into the world of sheet mulching and explore how this simple yet powerful approach can benefit your garden and the environment.

Years ago, we had all the grass in the front yard of the property removed and began sheet mulching so we could swap our lack luster lawn for an herb spiral with a wide variety of California natives. We wanted to grow food and medicine, not lawns -- while saving water and enriching the environment around us. 

After loads and loads of wheelbarrows with woodchips, plenty yards of cardboard and compost (it is not so labor intensive, but may take a few applications to yield the desired result), the grass was no more. Judith would begin to plant her herb spiral garden and before you know it, the space was totally transformed and brilliant. 

 This hack takes minimal effort but offers great reward! So, without further ado, let's delve into the world of sheet mulching and explore how this simple yet powerful approach can benefit your garden and the environment.

The Basics of Sheet Mulching

Sheet mulching is a process that mimics natural decomposition, fostering a healthy soil ecosystem. The method typically involves layering organic materials directly onto the soil surface, creating a "mulch sandwich" that nurtures the underlying soil. The key components of sheet mulching can include:

1. Cardboard or Newspaper Base:

   • The first layer consists of cardboard or several layers of newspaper. This serves as a barrier to suppress weeds and grass underneath while allowing water to penetrate.
   • When using cardboard, it is best to use plain cardboard without colored or glossy print on it. Remove all tapes, labels and any non-biodegradable materials. 

2. Carbon-Rich "Browns":

   • The next layer involves adding carbon-rich materials such as straw, dry leaves, or shredded newspaper. These "browns" provide structure to the mulch and contribute to soil aeration.

3. Nitrogen-Rich "Greens":

   • Followed by a layer of nitrogen-rich materials like kitchen scraps, grass clippings, or fresh green plants. This layer adds essential nutrients to the soil and initiates the decomposition process.

4. Compost:

   • A layer of finished compost enriches the soil with beneficial microorganisms and provides a diverse array of nutrients for plant growth.

5. Top Mulch Layer:

   • Finally, a top layer of straw or wood chips helps retain moisture, regulate temperature, and further suppress weed growth.

We personally use extra cardboard and compost topped with a generous amount of woodchips and have found that to work just as well. How you like your lasagna is up to you! :)  Keep in mind that you want more carbon than nitrogen similar to a compost pile to have the right balance. 

 There's a handful of places we have sourced cardboard from which is worth thinking about since most of us don't have a ton laying around. 

From grocery stores, to bookstores, furniture warehouses and even Facebook marketplace and Nextdoor -- If you ask and look around, you will be surprised at how many resources you have in your area! 

How To Start 

The first thing you want to do is prepare the area. You want to make sure all grass, shrubbery, etc. is cut all the way down before you lay down your first materials.

Water the area and get rid of bigger debris that will take longer to decompose. If the soil in the area is compacted or clay dominant, then you will want to use a fork or similar tool to break it up. Adding any desired amendments to the soil would be done at this point as well. 

Next, you want to gather all of your materials per the list above. After you have all of your materials you will want to start with covering the area with a nitrogen-rich material like grass clipping to really get the decomposers in the soil excited. Once this is done you are ready to lay your newspaper, cardboard, and other carbon and nitrogen sources.

Keep alternating materials layering them on top of each other until you have a good 3-4 inches minimum of mulch down. Give a heavy water weekly and let nature take care of the rest! 

Benefits of Sheet Mulching

1. Weed Suppression:

   • The initial cardboard or newspaper layer acts as a natural weed barrier, reducing the need for synthetic herbicides.

2. Soil Enrichment:

   • The combination of nitrogen-rich greens and carbon-rich browns, along with compost, promotes microbial activity, enhances soil structure, and boosts nutrient levels.

3. Water Conservation:

   • The mulch layers help retain soil moisture by preventing evaporation, reducing the frequency of irrigation.

4. Erosion Prevention:

   • Sheet mulching protects against soil erosion, particularly on sloped surfaces, by providing a protective cover.

5. Sustainability:

   • Sheet mulching recycles organic materials, diverting them from landfills, and contributes to a more sustainable and regenerative approach to gardening.

6. Carbon Sequestration:

• Organic matter used in sheet mulching, as it decomposes, contributes to carbon sequestration in the soil. This helps mitigate climate change by storing carbon in the ground rather than releasing it into the atmosphere.

A Few More Tips

• Patience is key. Sheet mulching is a gradual process. Allow time for the layers to decompose and integrate into the soil before planting.
• Fall/Winter is the ideal time to sheet mulch give a few months before planting in Spring.
• Aim for a balance in layer thickness. Too thin may not provide adequate weed suppression, while overly thick layers can hinder water penetration.
• Water the layers well after each addition to encourage decomposition and settle the materials. 
• DON'T OVERTHINK IT!

In conclusion, sheet mulching stands out as a sustainable gardening technique that goes beyond the surface benefits. Whether you're an experienced gardener or just starting, incorporate sheet mulching into your gardening routine to nurture the soil, reduce the need for any potentially harmful inputs, and promote overall healthier soil and vibrant plant life.