For effective use, pre-emergent herbicides need to be applied before weed seeds germinate.
Winter Grass (Poa annua)
Wintergrass seed germination can occur from late Summer through to Autumn. This varies across Australia, but if soil temperatures are consecutively around 12°C range in your area this is ideal for Winter grass seed germination.
To prevent Winter grass seed germination, apply your pre-emergent before soil temperatures get below 12°C going into Autumn.
Summer Grass and Crab Grass (Digitaria sp.)
Summer grass and Crab grass seed germination occurs when soil temperatures are between 12-15°C. This usually occurs during Spring.
Crowsfoot Grass (Eleusine indica)
Crowsfoot grass seed germination takes place when soil temperatures are between 15-18°C. This usually occurs in Spring.
To prevent Summer grass, Crab grass and Crowsfoot grass seed germination, apply your pre-emergent before soil temps start to reach 15°C coming out of Winter.
LawnPride Pre-Emergent Tech Sheet
Download our guide to plan your turf renovation and pre-emergent applications for maximum efficacy and efficiency.