The snow has melted and it's finally dry enough to rake and clean up your lawn. As you're getting up close and personal with your grass, you might notice there are thin or even bare patches. If you can see soil, so can the weed seeds and it's just a matter of time before they get a foothold and start to grow. Topdressing and overseeding your lawn this spring is the natural way to thicken your turf and crowd out undesirable weeds.
Topdressing
Topdressing involves the addition of a thin layer of good quality topsoil or compost on top of your lawn. This is especially important in new subdivisions built on little topsoil and thin lawns. Topdressing adds all-important organic matter to improve the condition of the soil.
Always use good quality compost and topsoil to ensure it is weed-free. Avoid using non-composted manures, they may contain weed and crabgrass seeds. Many Landscape Ontario member garden centres sell bags of top dressing that contain a blend of compost, soil, and peat moss.
The easiest way to topdress a lawn is to shovel or dump small piles of the soil mix all around your lawn and then spread it out into a ¼ to ½ layer using a hard rake. Don't leave the soil layer thick enough to smother the grass blades.
Overseeding
Overseeding improves your lawn's ability to resist weed and insect infestation by encouraging a healthy lawn. Avoid buying all purpose grass seed as there are high quality blends specifically labelled for sun and shade. Chose a blend with a mixture of several grass types as it will be more resistant to weeds and pests.
Topdressing and overseeding can be done together. The first step is to clean up the lawn with a fan rake to remove leaves, dead grass and other detritus of winter. Feather into the grass your topdressing mix, and then apply the grass seed to your lawn with a spreader or by hand. Distribute the seed as evenly as possible, then mix the seed and the soil together by tumbling them together using your leaf rake as a broom - holding it with the tines pointing upward together. Make sure the seed bed stays moist, either through rainfall or daily light watering, until the seeds begin to sprout.
When the new grass has grown to a height of 6 to 8 cm, it can be cut, but not shorter than 4 to 5 cm. Do not let the grass grow so long that it will not stand upright. Ensure that your mower blade is sharp to avoid tearing the grass plants.
