Weed suppresion


We are in Oshawa. We have several good sized perennial beds with decent loamy soil – well amended. They got a little out of control last summer, largely because I was away during prime gardening season. This year we dug up large portions of the beds, replanted and mulched heavily. What is our best strategy for weed suppression between now and spring? Should we mulch heavily for the winter?



Thank you for contacting Toronto Master Gardeners.

You sounds like you are off to a great start. When you dug up the bed to replant, weed stock (seeds lying dormant under the surface) do become exposed and start germinating. By heavily mulching you will have helped  to minimize this effect already.

At this point, moving forward the plants should not need you to disturb the soil next spring. By mulching through the summer and during the winter nutrients will slowly leach into the soil replenishing it. It will also help loosen up soil underneath encouraging good drainage and the formation of soil aggregates and air pockets for the roots. Worms and essential microbes will be attracted to the area and further improve the soil.

To continue mulching the area you may want to try different mulches. One of the best and least expensive mulches is leaf mulch. By collecting up fall leaves and mowing them you create a nourishing mulch which will breakdown through the winter and feed the garden ( do not use black walnut leaves for this purpose). Adding compost on top of the soil is also a valuable mulch. There are many mulches available at stores which can be used on top to give a nice finished look to your garden.

When mulching do be sure that there is a space between the mulch and the plant stems to allow air movement around the plant. If you have any woody plants this is critical to avoid any of the bark around the base of the trunk from remaining damp and starting to break down.

Continue as you are doing and mulch your beds. Minimize disturbance of the soil by leaving mulch on to breakdown and just keep adding on top. You should be able to reduce weeds this way and end up with healthy soil and a beautiful garden.

Good Luck!