Spring Lawn Preparation Guide for London, Ontario

1. Know When to Start in London

In London, Ontario, the last frost date typically falls in mid-to-late April, so resist the urge to start too early. Walking on frozen or waterlogged soil compacts it and damages tender grass roots that are just beginning to wake up. Wait until the ground has thawed completely and the soil is dry enough that it does not stick to your shoes before you begin any spring lawn work.

A good rule of thumb for the London area is to target the third or fourth week of April. Keep an eye on the Environment Canada forecast for our region and watch for consistent daytime highs above 10 degrees Celsius before diving in.

2. Raking and Dethatching After Winter

Winter leaves behind a mat of dead grass, fallen leaves, and debris that can smother your lawn and invite disease. A thorough raking with a stiff-tined rake removes this layer of thatch and allows air, water, and sunlight to reach the soil surface. In London, where heavy snow cover often presses debris flat against the ground, this step is especially important.

If the thatch layer is thicker than about half an inch, consider using a dethatching rake or a power dethatcher. Dethatching also helps break up any patches of snow mould, a common fungal issue in our region after prolonged snow cover. Clear all the raked material to the curb or compost it so your lawn can breathe.

3. First Mow: Timing and Technique

Your first mow of the season should happen once the grass is actively growing and reaches about 3 to 4 inches tall. In London, this usually lines up with early-to-mid May. For the first cut, set your mower blade a little higher than normal and remove only the top third of the grass blade to avoid stressing the turf.

Make sure your mower blade is freshly sharpened before the season begins. A dull blade tears the grass rather than cutting it cleanly, leaving ragged tips that turn brown and become entry points for disease. A clean cut promotes faster recovery and gives your lawn that crisp, professional look right from the start.

4. Spring Fertilization for Southwestern Ontario

Southwestern Ontario lawns benefit from a light spring fertilizer application once the grass has been mowed once or twice and is actively growing. Look for a slow-release granular fertilizer with a balanced or slightly higher nitrogen ratio to encourage strong green growth. Applying too early, before the grass is growing, wastes product and can promote weed growth instead.

For London-area lawns, mid-to-late May is typically ideal. Keep in mind that Ontario's cosmetic pesticide ban means you should choose fertilizer products that are compliant with provincial regulations. If you are unsure which product to use, a local lawn care professional can recommend the right blend for your soil type.

Consider getting a soil test done through a local garden centre or the Ontario Ministry of Agriculture. Knowing your soil's pH and nutrient levels helps you apply exactly what your lawn needs and nothing it does not.

5. Addressing Winter Damage: Bare Spots and Salt Damage

London winters are tough on lawns. Bare spots caused by snow mould, ice, or heavy foot traffic are common, and road salt that splashes onto grass along driveways and sidewalks can leave brown, dead patches. Start by flushing salt-damaged areas with a generous watering to help leach the sodium out of the soil.

For bare spots, loosen the top inch of soil with a garden rake, spread a quality grass seed blend suited to our climate (a mix of Kentucky bluegrass and perennial ryegrass works well in London), and cover lightly with a thin layer of compost or topsoil. Keep the seeded areas consistently moist until the new grass is established.

If the damage is extensive or you are dealing with large salt-affected areas along your driveway, it may be worth having a professional assess the situation. Sometimes adding gypsum to the soil can help counteract sodium buildup and speed up recovery.