About Tiller
Tiller is built by Rob Zimmerman. It is an independent project — not a lawn-care company, not a product brand, and not a franchise looking for your address.
Why this exists
Most lawn advice on the internet is written for a climate and then published as if it were universal. Northern advice assumes northern summers. Southern advice assumes southern winters. If you live anywhere in between — and a lot of the country does — both are close enough to sound right and wrong enough to cost you a season.
I grew up in and around hardware retail, from age 14 to 33, on the counter side of exactly this problem: people arriving with a bag of dead lawn and a product recommendation that was correct somewhere else. The honest answer was almost always about timing, and timing is the thing generic advice throws away first.
Tiller is an attempt to keep the timing.
Where the numbers come from
Every seasonal window, rate, and threshold on this site traces to a published source. The ones doing the most work:
- University extension publications — Virginia Cooperative Extension, NC State Extension, and University of Maryland Extension carry most of the species and calendar guidance, and are cited on the page that uses them.
- NOAA NCEI US Climate Normals, 1991–2020 — per-station freeze and frost normals, read from the station CSV files rather than the API, which still serves the older 1981–2010 values. Each state's figure carries its station ID, completeness flag, and years of record.
- Product labels — application rates and restrictions come from the label, never from a summary of the label.
Where a source disagrees with what would be convenient to say, the source wins. Several guides are deliberately held back from publication because the regional guidance is not good enough yet.
What this site will not do
- Invent a number. If a figure has no traceable source it does not ship. This is enforced in the build, not by good intentions — the generator fails on unsourced values.
- Put safety behind a paywall. Anything that keeps you from hurting your lawn, yourself, or your neighbour's water is free and stays free.
- Pretend to be local when it isn't. Some states are honest to a single date and some are not. Where a state-level number spans weeks, the guides say so and point you at your county extension office.
Corrections
If something here is wrong, I want to know — particularly on agronomy and on regional timing, where being confidently wrong does real damage. Write to support@tillerlawn.com and point at the page.
Press and research enquiries are welcome at the same address.