Sheet mulching grass in early April for May planting?

(Question)

I have a small yard of patchy grass (14’x20′). I would like to convert it to just garden this year. It has been suggested that I cut up the sod and turn it over, but I’m looking for other ideas. Could I sheet mulch it now (early April) and plant my flowers and shrubs this May? I know, I should have done it last fall, but it’s too late for that :-) Thanks for any advice.

(Answer)

Thank you for contacting Toronto Master Gardeners.

The latest research shows that digging soil breaks down the structure of the soil which can take a long time to reform. When you lose structure in the soil it will not hold water and nutrients in ways accessible to the plants as well. With digging you also expose weed seeds which will then germinate and create more work for you. Digging disturbs the delicate ecosystem of microbes, beneficial fungi, insects and worms that have developed over time.

Looking at your picture, it looks like you could use a bit more soil in the bed as it is quite a bit lower than the edge. Probably the easiest way to deal with the space would be to add several inches more of soil and compost on top of the bed to bring up the soil level. This will have the same effect as sheet mulching. On top of the soil put a thick layer ( a few inches deep ) of wood chips to impede weed growth and help contain moisture and soil structure. The microbes, insects and worms from below will slowly start working their way up loosening the ground below and creating new structure in the added soil. Your local nursery should have soil available with a mixture of compost already worked in.

You should be able to then dig in your new plants and shrubs with little difficulty and should not need to add any further fertilizers to the plot. Down the road it is advised to do soil testing to ensure your plants have the nutrients they need.

There is further information on soil health in the article from our library of answers attached below.

Soil Preparation and Planting