Most lawn advice comes as a calendar: put down crabgrass preventer in March, seed in September, feed around Thanksgiving. But a March in Atlanta and a March in Minneapolis have little in common, and no two springs in the same town are alike. The things that actually set the timing, weed seeds sprouting, grass seed germinating, roots taking up fertilizer, all follow soil temperature.
Soilclock estimates that soil temperature every day for 272 US cities, compares it with the same date in past years, and turns it into plain answers: is the pre-emergent window open, is it too late to seed, is it too late to feed. Each city page shows the typical dates for that place, worked out from about 20 years of its own weather, and how this year compares.
How it is made
Everything is built from public data: NOAA and National Weather Service weather, USDA soil sensors and Census geography. A script refreshes the data every morning and rebuilds the site. The soil model and its error are documented in full on the methodology page, and every source is listed on data sources.
What it is not
It is not a soil probe in your yard, and it does not replace your state extension service or a product label. Shade, slope, soil type and watering all change what is happening under your own grass. Use the pages for the trend and the timing, and a thermometer for your exact spot.
Advertising
The site is free to use and may show ads. Ads never change the data or the advice.
Questions or corrections: [email protected].