When to Water
iOS Universel / Style de vie
Stop guessing when to water your garden. When to Water uses real evapotranspiration science (ET₀) combined with local rain history and weather forecasts to tell you exactly when your garden needs water — and when it doesn’t.
Water smarter, not more. By watering only when your garden actually needs it, you reduce water waste, lower your water bill, and do your part for the environment. Every drop counts — When to Water helps you make sure none are wasted.
Unlike indoor plant care apps, When to Water is built specifically for outdoor gardens. And unlike smart irrigation systems, you don’t need any hardware, sensors, or hoses. Just open the app and get a clear recommendation.
How it works
When to Water calculates daily water loss from your soil using the Hargreaves evapotranspiration method — the same approach used in professional agriculture. It factors in recent rainfall, upcoming forecasts, and your local weather conditions to give you a personalized best-day-to-water recommendation.
What the app does
Best day to water: Scans the 5-day forecast and picks the last dry day before a long dry spell — so your soil stays moist as long as possible.
How long to water: Tells you exactly how many minutes per m² to apply, based on your garden’s current water deficit.
Rain history + forecast: Combines 7 days of historical rainfall with the upcoming forecast for a complete picture.
Watering calendar: Log the days you watered and track your garden’s history month by month. Your logged watering days are factored into future recommendations, so the advice always accounts for what you’ve already done.
Push notifications: Receive a gentle morning reminder on days when watering is recommended.
Works anywhere: Search for any city worldwide — the advice automatically adjusts for your latitude and climate.
Offline support: Last known weather data is cached so the app stays useful even without a connection.
Designed for home gardeners
Whether you grow vegetables, flowers, or a lawn, When to Water helps you build a smarter watering habit. No complicated settings — just open the app, see the advice, and water with confidence.
Privacy first
No account required. The app uses anonymous authentication, so your data stays yours. No email address, no password, no tracking.
When to Water is free to use. Save water, save money, and keep your garden thriving.