Louisiana · 16 cities · spring 2026
When to apply crabgrass preventer in Louisiana
Last spring's pre-emergent window, largest Louisiana cities
Each bar runs from the day the soil held 50°F to the day it held 55°F (2026).
- 50°F to 55°F
Every Louisiana city
Spring 2026 dates and today's verdict.
| City | Held 50°F (2026) | Held 55°F (2026) | Soil today | Today |
|---|---|---|---|---|
| New Orleans, LA | Feb 6 | Feb 7 | 71°F | Season over |
| Baton Rouge, LA | Feb 7 | Feb 10 | 70°F | Season over |
| Shreveport, LA | Feb 7 | Feb 9 | 71°F | Season over |
| Lafayette, LA | Feb 7 | Feb 10 | 70°F | Season over |
| Lake Charles, LA | Feb 6 | Feb 8 | 67°F | Season over |
| Monroe, LA | Feb 9 | Feb 11 | 67°F | Season over |
| Alexandria, LA | Feb 7 | Feb 10 | 68°F | Season over |
| Houma, LA | Feb 6 | Feb 8 | 70°F | Season over |
| New Iberia, LA | Feb 6 | Feb 10 | 70°F | Season over |
| Laplace, LA | Feb 6 | Feb 10 | 70°F | Season over |
| Slidell, LA | Feb 7 | Feb 10 | 68°F | Season over |
| Prairieville, LA | Feb 7 | Feb 10 | 69°F | Season over |
| Ruston, LA | Feb 9 | Feb 10 | 66°F | Season over |
| Hammond, LA | Feb 7 | Feb 11 | 68°F | Season over |
| Natchitoches, LA | Feb 7 | Feb 10 | 68°F | Season over |
| Opelousas, LA | Feb 7 | Feb 10 | 69°F | Season over |
Crabgrass seeds start to germinate once the top 2 to 4 inches of soil stay near 55°F for several days. A pre-emergent works as a barrier in the soil, so it has to be down and watered in before that: the usual advice is to apply it while the soil holds 50 to 55°F. The dates here are when the modelled soil began to hold each temperature last spring; this year's window will move with the weather, which is why each city page shows today's reading and the 7-day forecast.
Questions
- When should I put down crabgrass preventer in Louisiana?
- When the soil holds 50 to 55°F. Last spring that was around Feb 7 to Feb 10 across 16 Louisiana cities, earlier in the south and in cities.
- Is it too late to apply pre-emergent?
- Once the soil has held 55°F for a week or more, crabgrass is germinating and a pre-emergent will not stop the seedlings already up. Each city page says which side of that line it is on today.
Soil temperature today in Louisiana →
Data: Global Forecast System (GFS) 0.25°, soil temperature 0–10 cm (TSOIL) (NOAA National Centers for Environmental Prediction (NCEP)); GeoNames gazetteer (cities15000) (GeoNames).