Watering your lawn may seem straightforward, but it’s an often misunderstood aspect of lawn care.

Overwatering wastes water and money, while underwatering stresses your grass, leading to patchy, unhealthy lawns.

With research-backed knowledge, there’s now a simpler, smarter way to know exactly when to water your lawn: the Lawn Irrigation Scheduler.

How the Lawn Irrigation Scheduler Works

The Lawn Irrigation Scheduler uses weather data and research-based calculations to determine the ideal days to water your lawn.

Watering your lawn properly starts with understanding its water needs, which are largely influenced by evapotranspiration (ET).

Evapotranspiration is the process through which water leaves your lawn and enters the atmosphere. It combines:

Evaporation – Water evaporating from the soil surface.

Transpiration – Water absorbed by roots and released as vapour through grass leaves.

Your watering needs are obviously affected by local rainfall. The tool imports forecasted rainfall and allows you to edit the amount you've received, so you can adjust it based on your rain gauge readings or other data you feel is more accurate.

The process to use the tool is very straight-forward:

1. User Input – Enter your postcode, the last time you watered your lawn, your soil type (sandy, loamy or clay) and how much you irrigate per session in mm.

2. Weather Data Fetching – The tool retrieves past and forecasted evapotranspiration and rainfall data for your location.

3. Calculation – It keeps a running calculation of water loss and replenishment.

4. Custom Schedule Generation – Based on this information, the scheduler provides a tailored watering schedule, showing exactly which days to water your lawn.

With this tool, you no longer rely on vague advice like "water 1–3 times a week." Instead, you’ll use precise data to ensure your lawn is watered at the right time.

Why Proper Watering Matters

Your lawn’s water needs vary based on climate, and soil conditions (and grass type, however that hasn't been factored in yet).

Irrigating based on evapotranspiration (ET) and rainfall data ensures that water is applied at rates matching the turf's physiological needs.

Research confirms significant reductions in water usage without compromising turf quality when irrigation schedules are aligned with ET rates​​.

Irrigating with deficit ET amounts (less than ET loss, which is factored into the tool's calculations) has shown to increase root biomass and length, which improve the turf's resilience and water intake.

Water savings have been shown to be at least 25% and up to 88% using ET-based irrigation.

Why It’s Better Than Guesswork

Traditional advice like "water 1–3 times a week" doesn’t account for variables such as recent rainfall, soil type, or differences in local evapotranspiration and daily weather conditions.

The Lawn Irrigation Scheduler tailors its recommendations to your lawn’s specific needs, ensuring you water only when necessary.

This precision saves time, conserves water, and keeps your lawn at its healthiest.

How can this tool be improved?

If this is something you find useful, or you have any suggestions, please let us know either on Facebook or through our Contact form.

If there is enough interest, we will look at incorporating it into the Lawnsmith app with features to provide notifications so you'll never miss your ideal watering days!

Let us know what you think!