Creating a garden bed in which you can reliably grow healthy plants for years to come is well worth a bit of patience and some extra effort. But we can reduce this effort by building a no-dig garden. The no-dig garden process has similarities to the sheet mulching method which is an effective approach and is also known as lasagna gardening.
Both methods require that the gardener creates layers organic materials that ultimately compost down and produce a soil that is very high in organic matter and is therefore nutrient rich and retains moisture. The sheet mulching method also has the effect of suppressing weed growth.
In this article, I will explain the step-by-step process of building a garden bed using the sheet mulching method in order to provide a rich and long term base for healthy plant growth for years to come.
Understanding the Sheet Mulching Method
What is Sheet Mulching?
Sheet mulching is a no-dig gardening technique that utilizes natural composting processes. By layering organic materials directly onto the soil, you create a nutrient-rich environment that promotes healthy plant growth while reducing the need for traditional digging.
What are the Benefits of Sheet Mulching?
There are numerous benefits to using the sheet mulching technique to building your own no-dig garden. These include:
- Weed Suppression: One of the primary advantages of sheet mulching is its ability to smother weeds. This then reduces the need for herbicides and constant weeding.
- Improved Soil Structure: Over time, the organic layers break down, enhancing soil structure and promoting aeration.
- Moisture Retention: Sheet mulching results in a good level of organic material being present in the soil which then helps the soil retain moisture, reducing water requirements and promoting plant heat resilience.
- Nutrient Enrichment: As the organic materials decompose, they release nutrients into the soil, providing a steady source of nourishment for plants.
How to Build a Sheet Mulch Garden Bed
Choose the Right Location:
Select a sunny spot for your garden bed, as most vegetables and flowers thrive in full sunlight. In the southern hemisphere a north facing aspect is best, while a south facing aspect is best in the northern hemisphere. Ensure the area is relatively flat and accessible for watering. If you selected area is sloping, you may need to consider using terracing to create level spaces - garden beds that are sloping can suffer from terrible erosion in heavy rains.
Gather the Materials:
Collect a variety of organic materials in quantities suitable for covering your garden bed area:
- Cardboard or Newspaper: Acts as the base layer to suppress weeds.
- Compost or Well-Decomposed Manure: Adds nutrients and additional organic structure to the soil.
- Straw or Hay: Provides insulation, helps with moisture retention, and adds bulk to the layers.
- Leaves or Grass Clippings: Provides high-carbon materials that contribute to the decomposition process.
- Wood Chips or Mulch: Acts as a protective layer and reduce the loss of moisture from the soil by evaporation.
Clear the Area:
Remove existing weeds or grass from the chosen location. This step ensures that your sheet mulch is in direct contact with the soil, maximising its effectiveness.
Add organic fertilizer and gypsum if much clay is present
The organic fertilizer will help to encourage worm activity in the soil as well as producing a nutrient rich foundation for your soil. Gypsum will help to break down the clay releasing the nutrients it contains and reducing the compaction of the soil.
Lay the Base Layer:
Lightly water the cardboard or newspaper to help it integrate in to the soil and encourage decomposition. This step promotes a smoother blending of the organic layers.
Layer with Straw or Hay:
Apply a generous layer of straw or hay to the compost. This layer acts as an insulator, aids in moisture retention, and introduces additional organic matter to the soil.
Incorporate Leaves or Grass Clippings:
Add a layer of leaves or grass clippings to contribute to the decomposition process. These materials are high in carbon and provide essential structure to the sheet mulch.
Add organic fertilizer:
Good options include blood and bone and well aged chicken manure. This contributes to a nutrient rich soil as well as helping to encourage worm activity and activation of the composting process,
Add Compost or Manure:
Spread a layer of compost or well-decomposed manure evenly over the area. This provides a nutrient-rich foundation for your plants. It also contributes to the organic material building up in the soil and helping to retain moisture with it.
Repeat the Process:
Continue layering the materials, alternating between nitrogen-rich (green) and carbon-rich (brown) components. Aim for a total minimum height of 30cm (12 inches) for optimal results. It is best to err on the side of having a little too much than not enough.
Finish with Mulch:
Top off your sheet mulch bed with a layer of mulch. This protective layer helps conserve moisture, and suppresses weed growth. I tend to use mulches such as sugar cane mulch, hay or straw for this purpose. Some people will recommend wood chip, but I prefer to not use wood chip for this purpose - it takes a long time to decompose and many forums have suggested that when dug in to the soil, it can tie up nitrogen as it decomposes. I therefore tend to use wood chip on perennial gardens, that are well established.
Water Thoroughly:
After completing the layering process, water the sheet mulch thoroughly. This helps settle the layers and initiates the decomposition process.
Maintaining and Planting in Your Sheet Mulch Bed
Planting in Sheet Mulch:
Create planting pockets by pushing aside the mulch and adding a layer of compost or potting mix. Plant your seeds or seedlings in these enriched pockets.
Sheet mulch beds generally require less frequent watering due to their excellent moisture retention capabilities. Water deeply to encourage plant roots to grow deeper into the soil.
Mulch Maintenance:
Periodically replenish the top layer of mulch to maintain weed suppression and moisture retention.
Fertilizing:
While the sheet mulch provides a nutrient-rich environment, consider adding additional compost or organic fertilizer as needed during the growing season.
Weed Emergence:
If weeds manage to poke through the sheet mulch, simply pull them out by hand. The layering technique minimizes weed growth, but occasional maintenance may be required.
Be Patient:
Sheet mulching is a long-term investment in your garden's health. Be patient and allow the layers to decompose gradually, providing a sustainable and nutrient-rich environment for your plants.
Building a garden bed using the sheet mulching method is a sustainable and effective way to create a thriving garden. By following this process, you not only develop healthier soil but you also reduce the need for constant weeding and minimize water usage.
