Stop guessing the best day to treat your lawn.
Fertilizer, grass seed, pre-emergent, weed killer: put any of them down on the wrong day and the rain just washes it away. lawn.tools reads your local hourly forecast and hands you the one day that actually works. About two minutes, no guesswork.
- Free, no account needed
- Ready in about two minutes
- Every verdict explains the why
How it works
- Step 1
Tell us your ZIP and product
Pick what you're putting down: granular fertilizer, grass seed, pre-emergent, weed & feed, and more.
- Step 2
We read your hourly forecast
The next five days get ranked against the rule for your product: enough rain to water it in, or a dry window so it isn't washed off.
- Step 3
Get the day, and the why
A clear verdict in plain language, with the reasoning spelled out, so you go once, on the right day, and don't waste a bag of product on the wrong one. No jargon, no guessing.
Built to be right
Anyone can put a calendar on a website. The hard part is being correct, and showing the work.
Backed by turf science
The rules behind each verdict come from published agronomy (how much rain waters in a granular app, how long a foliar spray needs to stay dry), not vibes.
Always the why, never just a date
Every verdict explains its reasoning in plain language, so you can act on it with confidence and get on with your weekend, not second-guess an app.
Honest about limits
Forecasts change and labels rule. When no day works on rain alone, we say so, and tell you your best hand-watering window instead.
Guides
Latest lawn care guides
Browse all guidesJuly 17, 2026 · 8 min read
How to get rid of chinch bugs: confirm them first, then time the treatment
Confirm chinch bugs with a coffee-can float test before you spray, then treat only if you are at or above the threshold, timed to hot, dry weather once nymphs have hatched.
July 15, 2026 · 8 min read
When to apply grub control: the summer window and how to water it in
Curative grub control goes down in mid to late summer, after the eggs hatch but while grubs are still small and feeding near the surface. Here is the regional timing and how to water it in.
July 11, 2026 · 6 min read
How much water after fertilizing? The watering-in numbers
Granular fertilizer needs about a tenth of an inch of water to move nutrients into the soil. Here is the number, the why, and the timing.
The tools
Watering-in timer
The best day to apply fertilizer, seed, pre-emergent, weed killer, and more, ranked from your next five days of local weather.
More tools are on the way: soil temperature lookup, application calculators, and a personalized lawn calendar.