CGM - how long before the pre-emergent effects wear off?

[Pandu]

I live in Plano & had applied CGM in Feb 05 to my bermuda lawn. I want to spread some grass seeds on the bermuda as there are patches where the bermuda did not come back this season. Will it be an exercise in futility since the CGM will prevent the grass seeds from germinating? Also, I have common bermuda grass & the new seeds I purchased are of the hybrid bermuda Princess 77 variety - does anyone know if there will be any problems if I mix it up with the common bermuda grass (assuming they germinate)?

Thanks.

[Dchall_San_Antonio]

I can't help you with the mix, but my inclination would be to stick with the same variety.

I'm going to say don't seed until next month but not because of the CGM. Rather just because bermuda seed needs real warm soil. So far the bermuda in your area is late coming out of dormancy, so something is delaying things up there.

[epi 1:10,000]

The preemergent effect of cgm last about 6 weeks/8 weeks max. I dont know that I would mix the princess and the common....... Some say mixing bermuda varieties creates and ugly patchwork of differing textures and shades of green. If you dont mind the marbling effect them go for it.

[Magnus]

Can anyone confirm the 6-8 week pre-emergent effect of CGM? This seems to be a very long time to me.

[Dchall_San_Antonio]

I think it depends on how much you use and how wet it has been. If your CGM has been dry, it will last a lot longer without decomposing.