Spring Lawn Care in Scarborough: What to Do in April & May
Spring Lawn Care in Scarborough: What to Do in April and May
If you live in Scarborough, you already know that spring doesn't arrive on schedule. Some years the snow is gone by late March. Other years, you're still looking at ice patches in mid-April. But once the ground thaws and grass starts showing green at the base, there's a narrow window to get your lawn in shape for the rest of the year.
This guide breaks down exactly what to do in April and May -- the two months that matter most for lawn health in our area. Whether you're in Malvern, Highland Creek, or Agincourt, the timing is similar. The specifics depend on your soil, your grass type, and how much winter damage you're dealing with.
Why April and May Matter So Much
Grass in southern Ontario grows fastest in spring when soil temperatures are between 10-18 degrees Celsius. That aggressive growth period is your best opportunity to thicken the lawn, fill bare spots, and crowd out weeds before summer heat slows everything down.
Miss this window, and you spend the rest of the season playing catch-up. Get it right, and your lawn mostly takes care of itself through June, July, and August.
April: Getting Started
Know When the Ground Is Ready
The single biggest mistake homeowners make is starting too early. Walking on waterlogged soil compacts it, especially in Scarborough where most properties sit on heavy clay. Compacted soil means shallow roots, poor drainage, and weak grass all season.
The test: Walk across your lawn. If you leave visible footprints that don't spring back, the soil is still too wet. Wait another week. In most Scarborough neighbourhoods, the ground is firm enough to work on by the second or third week of April.
Clean Up Winter Debris
Before anything else, clear what winter left behind:
Fallen branches and twigs
Matted leaves (especially along fences and under hedges)
Road salt residue near driveways and sidewalks
Any visible snow mould -- grey or pink patches of matted, dead grass
Salt damage is common on Scarborough properties, particularly along boulevard edges and anywhere near a plowed driveway. Rake these areas thoroughly to remove contaminated soil crust from the grass surface.
First Mow of the Season
Your first cut sets the tone. Here's how to handle it:
Height: Set your mower to 3.5 inches. This is higher than most people cut, but taller grass develops deeper roots and shades out weed seeds.
Blade condition: Sharpen your mower blade before the first cut. A dull blade tears grass instead of cutting it cleanly, leaving ragged edges that turn brown and invite disease.
Bag the clippings on this first mow only. The first cut collects a lot of dead material and debris that you don't want sitting on the lawn. After this, switch to mulching -- the clippings feed the soil.
Frequency: Once grass is actively growing, mow weekly. Never remove more than one-third of the blade height in a single cut.
Core Aeration
If you do one thing for your lawn this spring, make it aeration. Scarborough's clay-heavy soil compacts over winter from freeze-thaw cycles, and compacted soil is the root cause of most lawn problems -- thin grass, pooling water, fertilizer that doesn't seem to work.
Core aeration pulls small plugs of soil out of the ground, creating channels for air, water, and nutrients to reach the root zone. Leave the plugs on the surface -- they break down within a couple of weeks and improve soil structure.
Best timing: Late April, once the grass is actively growing but before the heat of late spring. The soil should be moist but not soggy.
DIY or hire out? You can rent a core aerator from a local equipment rental shop. It's heavy equipment and the job takes a few hours for an average lot. Most homeowners find it easier to hire a professional for this one.
May: Feeding and Filling
Once you've mowed a few times and the grass is clearly growing, May is when you shift to building lawn density.
Overseeding Bare Patches
Winter kills grass. Salt kills grass. Heavy foot traffic kills grass. If your lawn has bare or thin patches, May is the time to fix them.
How to overseed effectively:
1. Rake the bare area to loosen the top layer of soil
2. Spread seed at the rate listed on the bag -- more is not better
3. Cover lightly with a thin layer of topsoil or compost (just enough to barely hide the seed)
4. Water lightly twice a day until the seed germinates (7-14 days depending on the mix)
Best grass seed for Scarborough:
Full sun areas: Kentucky Bluegrass or Perennial Ryegrass blend
Shaded areas (under mature maples, common in older Scarborough neighbourhoods): Fine Fescue blend
High-traffic areas (kids, dogs): Perennial Ryegrass -- it establishes fast and handles wear
If you aerated in late April, overseed immediately after. The aeration holes give seeds direct contact with soil, which dramatically improves germination rates.
Weed Prevention
Timing is critical for weed control. Crabgrass -- the most common summer annual weed in Scarborough lawns -- germinates when soil temperatures hit about 15 degrees Celsius. In our area, that typically happens in the first two weeks of May.
Pre-emergent herbicide (like corn gluten meal for an organic option) must be applied before crabgrass germinates. Once you see crabgrass, it's too late for prevention -- you're stuck pulling it by hand or spot-treating all summer.
Important: Don't apply pre-emergent herbicide in areas where you've overseeded. It prevents all seeds from germinating, including your grass seed. Choose one or the other for each section of the lawn.
For broadleaf weeds like dandelions, targeted spot treatment is more effective than blanket spraying. A healthy, thick lawn is the best long-term weed defense -- dense grass crowds out weed seedlings before they establish.
Fertilizer Schedule
Ontario lawns benefit from a slow-release nitrogen fertilizer applied in mid to late May, once grass is actively growing and you've mowed at least three or four times.
What to use:
A balanced slow-release granular fertilizer (look for something like 20-5-10 or 24-4-8 on the bag)
Apply at the rate printed on the label -- more fertilizer does not mean greener grass, it means burnt grass
Water in lightly after applying, or apply before a forecasted rain
What to avoid:
Fast-release fertilizers that dump all the nitrogen at once (causes a flush of growth followed by stress)
Fertilizing before the grass is actively growing -- the nutrients wash away before roots can absorb them
Fertilizing during a dry spell without irrigation
A second application in early to mid-June keeps the lawn fed through the summer growth period. After that, hold off until September -- summer heat is not the time to push growth.
When to Call a Professional vs. DIY
Most spring lawn care is manageable for a homeowner with basic equipment. Raking, mowing, spot-seeding -- these are straightforward.
Where professional help makes a real difference:
Core aeration: The equipment is heavy, and rental plus your time often costs nearly as much as hiring someone who does it daily
Large-scale overseeding or sod repair: Getting even seed distribution and proper soil contact over a big area requires experience
Soil testing and amendment: If your lawn has persistent problems despite doing everything right, the issue is usually soil chemistry -- pH, nutrient levels, organic matter content. A professional can test and recommend specific amendments.
Grub damage: If you notice irregular brown patches that peel up like carpet, you may have grubs (European chafer beetle larvae). Treatment timing is specific and the products require careful application.
For regular weekly mowing and seasonal maintenance, a lawn care program takes all the timing decisions off your plate. We handle mowing height, frequency adjustments through the season, and fertilizer applications at the right intervals.
Month-by-Month Summary
| Task | When | Why |
|---|---|---|
| Debris cleanup and raking | Early to mid-April | Lets sunlight and air reach the soil |
| First mow (3.5 inches, bag clippings) | Mid to late April | Removes dead material, signals grass to grow |
| Core aeration | Late April | Breaks up compacted clay soil |
| Overseed bare patches | Early May (right after aeration) | Best germination window before summer heat |
| Pre-emergent weed control | First two weeks of May | Stops crabgrass before it germinates |
| First fertilizer application | Mid to late May | Feeds grass during peak growth period |
| Switch to weekly mowing (mulch clippings) | May onward | Returns nutrients to the soil |
Frequently Asked Questions
When should I start mowing in Scarborough?
Most Scarborough lawns are ready for the first cut between mid and late April, depending on the year. Wait until the ground is firm enough to walk on without leaving footprints and the grass shows active green growth at the base. Setting the mower to 3.5 inches for the first cut avoids stressing the grass too early.
Is spring aeration necessary every year?
In Scarborough, yes. Our clay-heavy soil compacts significantly over winter from freeze-thaw cycles. Annual spring aeration is the most effective way to improve root growth, drainage, and nutrient absorption. Lawns that skip aeration tend to thin out over time, regardless of how much fertilizer or water they receive.
Can I overseed and apply weed preventer at the same time?
No. Pre-emergent herbicides prevent all seeds from germinating, including grass seed. If you need to overseed bare patches and also prevent crabgrass, apply the weed preventer only to the established areas of the lawn and skip it where you've seeded. The new grass will need about six to eight weeks to establish before you can apply any herbicide in those spots.
How often should I fertilize my lawn in spring?
One application in mid to late May is sufficient for most Scarborough lawns. Use a slow-release granular fertilizer and follow the application rate on the bag. A second application in early June extends the feeding through summer. Avoid fertilizing before grass is actively growing or during hot, dry weather.
Get Your Lawn Ready This Spring
If your lawn took a beating this winter, now is the time to fix it. April and May are the two months where the right steps make the biggest difference for the rest of the year.
Dawn Till Dusk Landscaping offers lawn care services across Scarborough, Pickering, and North York -- from one-time spring cleanups to full-season maintenance programs. We've been working on properties in this area for over 15 years.
Request a free quote or check out our full range of landscaping services.
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