When to put down preemergent?

Before soil temps reach 70F. So very shortly depending on where you live.

Now for S LA

55° in the spring, 70° in the fall

I just bought some more Prodiamine.

0.45oz/1000sf within the next week or so (approaching 70degree soil temp rule)

Another 0.30oz/1000sf in the spring once temps are nearing 70 degrees again in the spring

ETA. I contacted Dr Ron Strahan, turf weed control specialist and professor with the LSU AgCenter today to verify if now was the appropriate time to apply pre-emergent herbicides in S LA for winter weeds his answer was “yes”.

Thanks to all in this thread for the heads up. I put some down yesterday

quote:

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Will preemergent prevent dollar weed ?

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No because dollarweed reproduces by underground rhizomes and tubers in addition to seeds.

Put it down tomorrow and hopefully we get sufficient rain next week to water it in. If not put out sprinklers. Just follow label instruction on the bag.

Not based on the weather forecast I’m looking at

This is from the Prodamine 65 WDG label “For optimum weed control, Prodiamine 65WDG should be activated by at least 0.5 inch of rainfall or irrigation before weed seeds germinate and within 14 days following application. See the map below for approximate crabgrass seed germination dates“.

I think that’s the generic form of prodiamine. I can’t comment on its effectiveness.