How much to water and what the soil temperature means for your grass right now, for northwest Raleigh and the Triangle. Updated every day, so you can go by what the lawn needs, not the calendar.
in one deep watering, early morning.
Just seeded? New seed is different: keep the top half inch of soil moist with light watering once or twice a day until it’s up and growing, whatever this says.
Rain is keeping up with what the grass is using.
| Day | Rain | Fescue used | Bermuda & zoysia used |
|---|---|---|---|
| Fri, Oct 16 | 0.53" | 0.12" | 0.09" |
| Sat, Oct 17 | 0.40" | 0.03" | 0.03" |
| Sun, Oct 18 | — | 0.09" | 0.07" |
| Mon, Oct 19 | — | 0.09" | 0.07" |
| Tue, Oct 20 | — | 0.10" | 0.08" |
| Wed, Oct 21 | — | 0.09" | 0.07" |
| Thu, Oct 22 | — | 0.09" | 0.07" |
| Fri, Oct 23 today | — | 0.10" | 0.07" |
| Sat, Oct 24 | — | 0.09" | 0.07" |
| Sun, Oct 25 | — | 0.09" | 0.07" |
| Mon, Oct 26 | — | 0.09" | 0.07" |
| Tue, Oct 27 | — | 0.10" | 0.07" |
| Wed, Oct 28 | — | 0.06" | 0.05" |
| Thu, Oct 29 | — | 0.09" | 0.07" |
Past rain is measured: CoCoRaHS volunteer rain gauges within about 6 miles of NW Raleigh, otherwise the RDU airport gauge via the Iowa Environmental Mesonet. Evapotranspiration and future rain for NW Raleigh from Open-Meteo (reference ET, FAO-56); future days are forecasts. Your yard's actual rain can differ, especially in summer storms.
Every sprinkler puts out water at a different speed, so minutes mean nothing until you measure yours once. Set 3 or 4 straight-sided cans (tuna cans work) around one zone, run it for exactly 15 minutes, and measure the water in each can with a ruler.
This week’s amount is filled in from the fescue number above. Water early in the morning. If water starts running off before the time is up (common on Raleigh clay), stop, wait an hour, and finish the rest.
Every day your lawn loses water two ways: evaporation from the soil and transpiration through the grass blades. Together that's evapotranspiration, or ET. Weather services calculate a "reference ET" from temperature, sun, wind and humidity. Tall fescue uses about 80% of it, bermuda and zoysia about 60%.
We add up what the grass used over the last week, subtract the rain, and look at the forecast for the next seven days. Extra rain from last week counts a little (the soil holds some), and a dry week means the lawn is starting behind.
Soil temperature, not the calendar, is what tells weeds to sprout and grass to wake up or slow down. Everything on a lawn program is timed to it: a warm February can put crabgrass ahead of schedule, and a cool spring can push it back two weeks. This is the daily average about 2 inches down, where most weed seeds sit.
| 2" soil temperature | What it means |
|---|---|
| Warming past 50°F late Feb – March | Time for the spring crabgrass preventer. It has to be down before crabgrass starts. |
| Steady 55°F and up late March – April | Crabgrass starts sprouting. Tall fescue is growing fast. |
| 60–65°F, rising April | Bermuda and zoysia green up. Once they're about half green, they're ready for their first feeding. |
| 80°F and up summer | Fescue slows down and just tries to get through the heat. Bermuda and zoysia are at their best. |
| Falling under 70°F September | Annual bluegrass (Poa annua) and other winter weeds start sprouting, so fall weed preventers go down. |
| 50s–60s, falling September – October | The best window for seeding tall fescue: warm soil for sprouting, cool air for growing. |
| Falling toward 50°F November | Bermuda and zoysia go dormant. Fescue keeps building roots, which is why late-fall feedings matter. |
Soil temperatures from Open-Meteo for NW Raleigh. Shady and sunny spots in the same yard can differ by several degrees.
Have a brown patch that watering isn't fixing, or a weed you can't name? Send a photo through the free photo checkup and I'll take a look.