[jaygrizzle]

There was a thread in the warm season forum that addressed this topic, but I was hoping to get some advice on cool season grasses. On my WBG Crabgrass Control it indicates to not apply when temperatures are above 90 degrees. I have some weeds that I want to spray, but with summer midwest temperatures I am not sure on best practices.

The last week or so week or so the temperatures have been in the low 90s with the last two days around 95. There is a front forecasted to come in this evening and temps are expected to be in the mid 80s for the next 3-4 days. The forecast for tonight at 7pm is 85 degrees and with a break in the hot weather I was thinking about spraying some weeds that have came in since the last time I was able to spray. For cool season grasses - is applying crabgrass killer with about a 4 day window of below 90 degree temps a sufficient amount of time or am I risking damage to the grass?

 

[jha4aamu]

im also located in st. louis and i have spot sprayed wbg for crabgrass the last few days and i havent seen any noticable damage to the grass. the weeds are all dead/shriveling up though!

 

[Budstl]

You can spray in the evening as long as it is below 90 degrees.

 

[jaygrizzle]

Thanks! I think I am going to go for it. If I sprayed this evening, would there be any risk to the effectiveness of the WBG if I watered a half inch or so the morning after? Or should I wait 24 hours after spraying to irrigate? I know they claim that it is rainproof in an hour, but with this small window of opportunity to spray, I want it to be effective as possible as there are rarely any times in July that are lower than 90 degrees.

 

[Budstl]

I think you should be ok. If you're concerned about it, the weather is supposed to be cooler tomorrow and Saturday. I'm planning on spraying Saturday evening.

Also jaygrizzle if you head over to the hometown section, we have a st louis thread going on over there.

 

[Meebs11]

Saint Louis boy as well yes you should be fine if you apply at a temp that is below what the label says. This heat is never ending in the lou!

 

[Still learnin]

You can spray in the evening as long as it is below 90 degrees.

This was touched on in the warm season grass section. Another member did this and it hurt his grass significantly. I believe @Greendoc states it needed to below the max temp for several days.