Soil Temperature Tracker

Q: What soil temperature does bermuda grass need to break dormancy?

Bermuda grass active growth and visible greenup require consistent soil temperatures approaching 65°F. Texas A&M AgriLife Extension notes that green-up and recovery begin when soil temperature reaches 65°F at depth with nighttime temperatures consistently above 60°F. A full fertilizer and PGR program is appropriate once active canopy growth is confirmed. Use the pre-emergent window — when 2-inch soil reaches 50–55°F — as a crabgrass prevention signal, not as a bermuda greenup trigger.

Q: What is the ideal soil temperature for zoysia grass?

Zoysia breaks dormancy slightly later than bermuda, typically when 2-inch soil temperature reaches 55–65°F. Apply pre-emergent before soil hits 65°F. A full fertilizer and PGR program is appropriate once soil consistently exceeds 65°F and visible greenup is confirmed, since zoysia often shows green later than bermuda at the same soil temperature.

Q: What soil temperature is too hot for lawn applications?

Above 80°F soil temperature, warm-season grasses are in full summer growth but stress risk increases. Kansas State Extension specifically warns against applying elemental sulfur to established turfgrass at air temperatures of 80°F or higher due to burn risk. University of Nebraska-Lincoln turfgrass research notes that cool-season grass growth stops when soil temperature in the surface inch reaches 77–80°F, with an energy deficit at 80–85°F. Monitor chinch bug pressure on St. Augustine during peak summer — University of Georgia extension research shows development accelerates significantly at 83°F.

Current soil temperature at surface, 2″, and 6″ depth for your lawn — with turf-specific guidance on what it means for your program.

Track soil temperature alerts and trends through the full season in the app.

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Weather data provided by Open-Meteo (open source, no API key required).

Soil Temperature Guide for Lawn Care

Soil temperature is the most reliable indicator for timing lawn care applications. Unlike air temperature or calendar date, soil temperature tells you exactly what is happening at the root zone — pre-emergent germination, root activity, and grass growth are all driven by soil temperature, not the forecast high.

This tracker shows current readings at three depths: surface (0 cm), approximately 2 inches (6 cm), and approximately 6 inches (18 cm). The 2-inch reading is most relevant for lawn care decisions — it reflects the rooting zone of warm-season grasses and the germination zone of most annual weeds. If you also want to track heat accumulation over the season, see the GDD Calculator.

Bermuda Grass Soil Temperature Windows

The crabgrass pre-emergent window for bermuda lawns opens when 2-inch soil temperature approaches 50–55°F — apply before crabgrass germinates (University of Minnesota Extension; Penn State Extension). Active bermuda growth and visible greenup require consistent soil temperatures near 65°F: Texas A&M AgriLife Extension notes that green-up and recovery begin when soil temperature reaches 65°F at depth with nighttime temperatures consistently above 60°F. A full fertilizer, herbicide, and PGR program is appropriate above 65°F with confirmed canopy growth. Kansas State Extension warns against applying elemental sulfur to established turfgrass when air temperature is 80°F or higher due to burn risk.

Zoysia Grass Soil Temperature

Zoysia breaks dormancy later than bermuda. University of Georgia extension resources indicate zoysia does not begin consistent greening until soil temperatures are at or above 62–65°F. The pre-emergent crabgrass window (50–55°F) applies to zoysia lawns as well. Hold fertility inputs until visual greenup is confirmed, since zoysia often reaches adequate soil temperature before the canopy is visibly green. Full program is appropriate above 65°F with confirmed active growth.

St. Augustine Soil Temperature

NC State Extension recommends waiting until May or two weeks after green-up (whichever is later) before the first nitrogen application, with 65°F cited as the active growth threshold. Clemson University Extension similarly notes new shoots emerge at 65°F. St. Augustine is more sensitive to herbicide injury than bermuda — confirm the product is labeled for St. Augustinegrass before applying. Most St. Augustine programs do not include PGR. Monitor for chinch bug pressure during summer; University of Georgia Extension research shows chinch bug development accelerates significantly at 83°F, with peak infestations in July–September.

Cool-Season Grass Soil Temperature

Penn State Extension documents that cool-season grasses (tall fescue, Kentucky bluegrass, perennial ryegrass) produce best root growth at soil temperatures between 50°F and 65°F — the ideal window for fertilization and overseeding. University of Nebraska-Lincoln turfgrass research notes that cool-season grass growth stops when soil temperature in the surface zone reaches 77–80°F, with an energy deficit above 80–85°F. The best growth window is spring and fall.

Research and extension sources

Frequently Asked Questions

What soil temperature does bermuda grass need to green up?

Active bermuda growth and visible greenup require consistent soil temperatures near 65°F. Texas A&M AgriLife Extension notes that green-up and recovery begin when soil temperature reaches 65°F with nighttime temperatures consistently above 60°F. The 50–55°F soil temperature threshold is relevant for crabgrass pre-emergent timing, not bermuda greenup. A full fertilizer and PGR program is appropriate once active canopy growth is confirmed.

What soil temperature should I use for pre-emergent timing?

Apply crabgrass pre-emergent when 2-inch soil temperature reaches 50–55°F for 3–5 consecutive days. Applying after soil consistently exceeds 55°F risks missing the window for summer annual weeds like crabgrass and goosegrass.

What is the ideal soil temperature for zoysia grass?

Zoysia breaks dormancy later than bermuda. University of Georgia extension resources indicate consistent greening does not begin until soil temperatures reach approximately 62–65°F. Apply pre-emergent for crabgrass before soil hits 55°F. Confirm visual greenup before applying nitrogen — zoysia often reaches adequate soil temperature before the canopy is visibly green.

What soil temperature is too hot for lawn applications?

Above 80°F, avoid elemental sulfur (burn risk increases significantly) and high-rate nitrogen applications under drought conditions. St. Augustine is heat-sensitive above 85°F. Cool-season grasses are typically stressed or dormant above 75°F soil temperature.