How can we keep weeds from regrowing?*


The backyard was cleared of weeds last fall but the roots are still in the ground. What is the best way to cover the ground to avoid regrowth of all the weeds – black plastic or other mulch?




One way to get rid of weeds is to starve them of the light they need for photosynthesis (to make food). Do this by covering the infested beds with cardboard, thick newspaper layers (don’t use cardboard or newspapers that are highly coloured, as the inks may not be healthy for the soil), or thick ground-cover fabric and cover these in turn with a thick layer of mulch. The covering may have to be kept in place for a whole year.

Black plastic sheeting can also be used, and this may work a bit faster than the other types of coverings, as it also heats the soil, increasing the weeds’ growth rate and breakdown.

Remember that whatever covering you use must be thick enough to ensure that all light is excluded. When you hold the covering up to the sun, if the light shows through, try using a double or triple layer.

As well, the sheeting needs to be weighed down carefully. And you need to be vigilant to catch & remove any weeds that peek through the edges of the covering material.

It is best to cover the ground starting in late winter – this ensures the weeds will die come spring.  Discard any weeds you “harvest”, don’t compost them.

Once you’ve gotten rid of the weeds, consider planting easy maintenance groundcovers like mosses, thyme, or many others. Landscape Ontario  has a list of perennials that can be used as ground covers.  These are desirable plants that will out-compete any weeds that want to take root.

Here are a couple of articles of interest: