Pre-Emergent Herbicide Timing in Kansas Lottery, KS
Spring crabgrass and fall poa annua prevention timing based on current modeled soil temperature estimates for this location.
Current Soil Temperature
The 2-inch soil temperature near Kansas Lottery, KS is currently 78.3°F, modeled from Open-Meteo for this location (no monitoring station within range; nearest is Ku-Nesa, 25.7 mi away).
Soil is well above the crabgrass germination threshold. If you have not yet applied spring pre-emergent, switch to a post-emergent strategy for visible weeds, and plan for the fall poa annua application described below.
The 55°F Rule
Crabgrass and most summer annual weeds begin germinating when the 2-inch soil temperature sustains 55°F for 3–5 consecutive days. Pre-emergent herbicides create a chemical barrier at the soil surface that prevents weed seeds from sprouting. The barrier must be in place before germination begins.
- Early application: Apply 1–2 weeks before the 55°F threshold is reached for best results.
- On-time application: Apply at the first sustained 55°F reading. Still effective, but the window is narrow.
- Late application: After crabgrass has sprouted, pre-emergent will not kill existing plants. Switch to post-emergent.
Fall Pre-Emergent Timing for Poa Annua
Pre-emergent has a second season. Poa annua (annual bluegrass) and other winter annual weeds germinate in fall as the 2-inch soil temperature drops back through 70°F after the summer peak, with most germination in the 65–70°F falling range. A fall application ahead of that crossing stops poa annua the same way a spring application stops crabgrass.
The Kansas Lottery lawn care schedule tracks this window live against daily station readings. For products, rates, and the germination research behind the thresholds, see the fall pre-emergent timing guide.
Product Selection and Application Tips
Look for products containing prodiamine, dithiopyr, or pendimethalin. Dithiopyr has mild post-emergent properties and can suppress very young crabgrass (1–2 leaf stage) even if applied slightly late.
- Application rate: Follow label rates for your lawn size. Over-application does not improve control and wastes product.
- Watering in: Water lightly (0.25–0.5 inches) within 24 hours to move the herbicide into the top soil layer where crabgrass seeds germinate.
- Annual maximums: Do not exceed the label's annual application limit. Split applications (spring + late summer) are allowed on some products.
- Reapplication: If heavy rain washes the product away within 48 hours, a second light application may be needed.
Related Resources
Full lawn care schedule for Kansas Lottery →
Spring pre-emergent herbicide guide →
Check pre-emergent window in Kansas Lottery
Enter your ZIP code to see current 2-inch soil temperatures and find out whether the crabgrass prevention window is still open.