I am planning to create a new garden bed near the foundation of my house. Should I remove the existing soil and if so, to what depth? I think I should lay down landscaping paper and would like to know if I should put Peat Moss down then top soil or how I would layer the garden base. I expect to plant box shrubs, Peonies, Irises and similar.
Thank you for contacting Toronto Master Gardeners. First steps I’d recommend to creating your new garden bed include: 1) ensuring there are no hidden utility lines (gas lines); 2) assessing the amount of sunlight the area receives each day; 3) assessing your current soil – sandy, well-draining, clay, hard-packed; and 4) performing a pH test on your soil. Information on soil testing & analysis and improving your soil fertility can be found at: Soil Fertility: A Toronto Master Gardeners Garden Guide. Understanding your growing conditions will ensure you choose the right plants for your new garden bed. There are a number of Gardening Guides you can reference to assist you in choosing your new plants.
To create your new bed, remove any sod and all weeds. We don’t recommend removing your existing soil as it will disturb the natural soil profile as well as disturb the seed bank that’s currently in the soil. Any viable seeds in your soil could then germinate and cause unwanted weeds for you to deal with in future. This is commonly called the “No Dig” method for creating garden beds. Landscape fabric is not advised as it disrupts the natural flow of water and oxygen in your soil as well as trapping roots as they grow from your new plants.
One additional note, remember to ensure your plantings will be at least a foot away from your home’s foundation – using their size at maturity. This prevents moisture build-up around the foundation and provides good air circulation for your plants to thrive. It will also allow light to reach your window and space for any maintenance of the foundation or window.
Once you’ve planted your new perennials and shrubs, add 2 to 3 inches of organic material (compost, arborist wood chips, leaf litter, etc.) on top of the planting surface. This will provide needed nutrients, inhibit the growth of weeds, as well as help with moisture retention (especially in a sunny location). No need for peat moss nor top soil. Continue to add organic material throughout the years to maintain healthy soil. Leaves are a great soil amendment. Rake leaves on to your new garden bed in the fall and leave them to decompose over time. More details on the use of leaves as a soil amendment can be found in: Spring Clean-up: A Toronto Master Gardeners Garden Guide and Putting the Garden to Bed: A Toronto Master Gardeners Guide.
Best of luck with your new garden bed!
May 10, 2023