Pre-Emergent should go down in Aug & Feb.
The soil temperature models are broken and dated.
We have shifted weed germination windows due to our decades of management pressure. Pendulum was one of the first pre-emergent on the market for turf and it has been in use since 1972. When Barricade came on the market it had a money back guarantee to golf course superintendents if applied by Sept. 1st in the South. Two years of paying claims and Sandoz backed up the money back guarantee to Aug. 15th. That was more than 25 years ago. Poa has been germinating earlier and earlier for decades. And later and later, with the late winter flush of emergence.
We germinate in the South:
Poa: Aug-May
Crab: April-Oct
Goose: May-Nov
Spurge: June-Oct
We germinate weeds every month of the across the bermuda growing region in the US.
Our Post-emergents continue to develop resistance. Chasing weeds with post emergents is a loosing strategy. You have to stop the weeds in the ground. That is the ONLY successful strategy. You can always be early with your Pre. Understand your chemistry and have realistic expectations for its residual control.
Specticle/Indazaflam: the only active that can go a full 6 months from a single app.
Prodiamine/Dithiopyr: both only last 4-5 months at their highest labeled rates
Pendulum: 2-3 months per application.
All cause root pruning if used above label rates or on too short an interval. Severe root pruning will lead to thin turf and ultimately dead turf for a long while.
Read your label. Plan accordingly.
My personal program is BioAdvanced 3in1 twice a year in Aug & Feb. It is what I also recommend to friends and family. Gives the best results with the fewest applications and readily available and affordable.
You can find BioAdvanced here:
My pre-emergent didn’t work this year, what should I do?
Use Negate as a post emergent spray. You can find a small bottle here: