We have a very large garden on the bluffs – sandy soil. While there are flower beds along the perimeters, there is a large stretch of grass that has full sun which I would like to replace with native perrenials. We are in the planning phase now, and want to ready the area for next spring. I see in your Q&A’s on lawn replacement that in one place you recommend turning the grass and putting a layer of compost on top – in that way the topsoil is not lost. My first question: is that really sufficient to suppress the grass from growing up through the layer of compost? My second question is whether it would be helpful to put cardboard/sheeting on top of the turned under grass this fall with mulch on top to ensure grass and (the many) violets don’t come through? My third question is whether it is ill-advised to turn the grass by using a sod-cutter (no more than 4 inches) – and then smothering? Lastly, when is the best time to do this so we are ready to plant in the spring?
Thank you for contacting the Toronto Master Gardeners regarding replacing your lawn with native perennials.
The techniques you mentioned in your post are all practical and can be used alone or in combination. They are explained in detail here.
In addition, we would like to suggest solarization and occultation. These two simple methods are also being used to remove existing vegetation and get ahead of weeds.
“Solarization is the process of placing a clear plastic tarp over a field, garden bed or lawn to heat up the soil underneath. The intention of solarization is to kill weeds or grass, though it can have added benefits of reducing pathogen populations in the soil.”
“Occultation is similar to solarization, but opaque coverings are used instead of clear.”
Both processes are described in detail in this article.
If you chose solarization over other available options, the earlier you start, the better – July is typically the hottest month in Toronto.
Furthermore, while you wait for your new garden bed to get ready by next spring, you might want to have a look at Perennials for Sandy Soils: A Toronto Master Gardeners Guide. There are a lot of options to choose from.
I hope you find this information helpful! Good luck and enjoy planting your new garden in spring!