when should i put down crabgrass preventer

You should put down crabgrass preventer in early spring, just before crabgrass seeds start to germinate—when soil temperatures are around 50–55°F for several days in a row.

Key timing rule

• The ideal window is right before soil reaches about 55°F and stays there for 2–3 days, because that is when crabgrass begins germinating.

• In many cooler-climate areas, this lines up roughly with mid‑April to early May , but local weather matters more than the calendar.

• Once it is past mid‑May in many northern regions, much of the crabgrass has started to germinate and pre‑emergents are far less effective.

Practical “yard signs” to watch

Homeowners often use simple cues instead of soil thermometers:

• Apply when:
  • Lawns are greening up but not growing fast yet.

* Soil temps have a **5‑day average above ~50°F** , but below the mid‑50s.

* In many areas, this is **late March to mid‑April** ; some university turf programs recommend **mid‑April to mid‑May** as the broad window.

• Try to time application just before a light rain so the product can be watered into the soil and form its protective barrier.

Regional nuance

• Cooler northern climates: often mid‑April to early May.

• Warmer regions (parts of the South): window may shift earlier into late winter or early March , since soils warm sooner.

If you want a one‑line rule of thumb to remember:

Put crabgrass preventer down in early spring when your soil first warms into the low‑50s, a bit before real spring growth and warm weather kick in.

Information gathered from public forums or data available on the internet and portrayed here.