After a summer of heat, foot traffic, dry periods, weeds, and regular mowing, your lawn may be looking a little thinner than it did in spring. Late summer into early fall is an excellent opportunity to help it recover before winter.
For cool season lawns common in Ontario, this time of year brings cooler air temperatures while the soil is still warm enough to support seed germination and root development.
Overseeding thin areas, improving seed to soil contact, watering correctly, and providing appropriate nutrients can help build a denser lawn before winter and give it a stronger start next spring.
What Is Overseeding?
Overseeding means spreading new grass seed over an existing lawn rather than removing the lawn and starting over.
It is commonly used to fill thin areas, repair small bare patches, increase turf density, and improve the overall appearance of a lawn.
The key to successful overseeding is good seed to soil contact. Grass seed that lands on thick thatch, leaves, or other debris may have difficulty establishing.
Why Overseed Before Winter?
Late summer and early fall can provide favorable growing conditions for the cool season grasses commonly used in Ontario lawns.
The intense heat of midsummer begins to ease while the soil remains warm enough for germination. This gives new grass an opportunity to establish before winter arrives.
A dense, healthy lawn also leaves less open space for weeds to establish and helps the turf recover from summer stress.
Who Should Overseed?
Overseeding may be helpful if your lawn has:
Thin or weak patches
Small bare areas
Damage from summer heat or drought
Heavy foot traffic
Uneven turf density
Areas recovering from pest or disease damage
However, grass seed will not solve every lawn problem.
If the same area becomes bare every year, determine what is causing the problem. Excessive shade, compacted soil, poor drainage, drought, heavy traffic, improper mowing, insects, or disease may be responsible.
Correcting the underlying issue gives your new grass a much better chance of surviving.
When Should You Work on Your Lawn?
For Ontario lawns, late summer into early fall is an important lawn care period.
Ontario turf management guidance identifies approximately mid August through mid September as an important period for providing established turf with appropriate nitrogen to help it recover from growing season stresses.
Overseeding should also be completed early enough to give new grass time to germinate and establish before consistently cold weather arrives.
Weather conditions matter too. Extremely hot or dry conditions can make seed establishment more difficult, so consider both the forecast and your ability to keep the newly seeded area consistently moist.
Where Should You Focus?
Walk around your lawn and identify the areas that need the most attention.
Thin areas where grass is still growing may benefit from overseeding.
Small bare patches may need to be lightly raked first so the seed can reach the soil.
High traffic areas may have compacted soil that makes it difficult for grass roots to grow.
Heavily compacted lawns may also benefit from core aeration before overseeding.
Pay attention to sunlight as well. A grass seed mixture intended for a sunny lawn may not perform as well in an area that receives significant shade.
How Do You Overseed Your Lawn?
Start by mowing the existing lawn so new seed has an easier time reaching the soil. Avoid scalping the grass. The goal is simply to reduce interference from existing growth.
Next, remove heavy accumulations of leaves, dead grass, and other debris.
Lightly rake bare or thin areas to expose some soil. If the lawn is heavily compacted, core aeration can also help improve growing conditions.
Choose a grass seed mixture appropriate for your lawn's sunlight, moisture, traffic, and growing conditions. Scotts Turf Builder grass seed products are available in different formulations, so check the package to determine which option is best suited to your lawn.
Spread the seed evenly and use the application rate provided on the package. Applying extra seed does not necessarily create a better lawn and can cause young grass plants to compete with each other.
Finally, gently rake the seeded area to improve contact between the seed and soil. Grass seed should remain close to the soil surface rather than being deeply buried.
How Should You Water New Grass Seed?
Moisture is one of the most important parts of successful germination.
During the germination period, the surface should remain consistently moist without becoming waterlogged. This may require lighter and more frequent watering than you would normally provide to an established lawn.
Avoid allowing germinating seed to repeatedly dry out.
At the same time, don't apply so much water that puddles develop or seed washes away.
Once the new grass has established and developed stronger roots, watering can gradually transition toward deeper and less frequent irrigation.
Always follow the watering directions provided with the grass seed you're using.
What About Fertilizer?
Grass requires nutrients to grow, but more fertilizer does not automatically mean better results.
Ontario turf guidance identifies mid August through mid September as an important period for applying appropriate nitrogen to established turf to help it recover from summer stresses.
For established home lawns, phosphorus generally should not be added unless a soil test indicates that it is required.
If you're establishing new grass, choose products appropriate for seeding and follow the directions on both the seed and fertilizer packaging.
Scotts Turf Builder lawn products provide different options depending on what you're trying to accomplish. Make sure the product you choose is appropriate for your lawn and apply only the recommended amount.
Don’t Forget the Leaves
As fall progresses, avoid allowing a thick layer of fallen leaves to remain over newly establishing grass.
Heavy leaf coverage can block sunlight and interfere with young seedlings.
Leaves can be removed or suitable amounts can be finely mulched with a mower instead of allowing thick mats to develop across the lawn.
Should You Keep Mowing?
Yes. Continue mowing while the grass is actively growing.
Use a sharp mower blade and avoid removing too much of the grass blade during a single mowing.
For Ontario home lawns, maintaining grass at approximately 2 to 3 inches high generally helps encourage healthy turf and root development.
Do not stop mowing simply because fall has arrived. Let the growth of the grass and weather conditions determine when mowing is no longer necessary.
Common Fall Lawn Mistakes
Some of the most common mistakes include waiting too late to overseed, spreading seed without creating good soil contact, allowing germinating seed to dry out, overwatering newly seeded areas, applying excessive seed, and choosing a grass mixture that does not suit the location.
Avoid automatically applying large amounts of fertilizer as well. The correct nutrients and application rate depend on the lawn, soil, time of year, and product being used.
It is also important to determine why your lawn became thin in the first place. If poor drainage, shade, compaction, or another underlying problem remains, simply adding more grass seed may only provide a temporary improvement.
A thicker spring lawn can start with the work you do in late summer and early fall.
Begin by identifying thin and bare areas and determining why they developed. Prepare the soil surface, choose an appropriate grass seed, spread it at the recommended rate, and create good contact between the seed and soil.
Keep newly seeded areas consistently moist while germination takes place, continue mowing as necessary, and provide appropriate nutrition based on your lawn's needs.
Taking care of these jobs before winter can help your lawn recover from summer stress, establish stronger turf, and give it a healthier start when spring returns.
Give Your Lawn a Fall Boost
Get your lawn ready for the season ahead with Scotts Turf Builder grass seed, lawn fertilizers, spreaders, and other lawn care essentials available at Ritchie Feed & Seed.
