How to water a lawn in Ontario
Almost everyone waters too often and too lightly, which trains the lawn to be fragile.
Watering is the easiest thing to get wrong, because the instinct — a little every day — produces exactly the opposite of what you want.
Deep and infrequent, and why
Roots grow toward moisture. Water lightly every day and the moisture never gets below the top couple of centimetres, so the roots stay there too. That lawn is entirely dependent on you and collapses the moment you go away for a week.
Water deeply and less often and the moisture penetrates, the roots follow it down, and the lawn develops a reserve it can draw on. That is a lawn that survives a dry July on its own.
Every light watering is a lesson to the lawn that it does not need deep roots.
The numbers
- Around 2.5 centimetres of water per week, including rainfall
- Delivered in one or two sessions, not seven
- Early morning, before the heat, so less is lost to evaporation
- Never in the evening, which leaves the leaf wet overnight and invites disease
To measure it, put an empty tuna tin on the lawn while the sprinkler runs and time how long it takes to fill 2.5 centimetres. That is your weekly run time.
What clay changes
Clay absorbs water slowly. Run a sprinkler at full output on compacted clay and most of it runs off before it soaks in, which is why properties on Peel clay often get less water into the soil than the run time suggests.
The fix is cycle-and-soak: run for fifteen minutes, stop for thirty, run again. The pause lets the surface absorb what it has taken before you add more. It doubles the water that actually reaches the roots.
The alternative
Let it go dormant. It is a legitimate choice, it costs nothing, and the lawn recovers when the rain returns. What does not work is watering enough to keep breaking dormancy without watering enough to sustain growth.