Hi all,
I have a question about applying herbicide to my Floratam St. Augustine lawn here in South Florida. The instructions on the herbicide label state not to apply it when temperatures exceed 90°F.
Check out my situation…
- Morning Application: I’m considering applying the herbicide in the morning when the temperature is around 83°F, but I know it will reach 90°F later in the day. Would it be okay to apply it in the morning under these conditions?
- Evening Application: Alternatively, I could apply it in the early evening when the temperature is around 89°F. It should drop to the low 80s overnight, but the forecast shows it will be 90°F by 10 a.m. the next day. Would applying it in the evening work in this scenario?
I’m trying to make sure I adhere to the application guidelines and avoid any potential damage to my lawn. Any advice or experience with similar situations will be greatly appreciated 
You need to apply the herbicide when it won’t go over 85°F before it dries. I’ve never seen a 90°F limit—85°F is usually the max I’ve read.
The big deal is that these herbicides are acidic. Check the ingredients. When the acids get too hot, they can harm your good grass too.
So, the main thing is to get it applied and make sure it dries before it hits 90°F.
I’d suggest doing it in the evening before it gets dark. The wind is usually calmer then too, so you won’t end up with the stuff blowing back in your face.
I’m in FL. I do it in the evening then water it in so it can sit all night
Yoh @LoganCasterpellJnr Many herbicides should not be watered in. The foliage absorbs the herbicide so you don’t want to wash it off.
Easyyy …I was mainly referring to stuff that Trejos you to water in in instructions like granular
You can go with either evening or early morning, but I’d lean towards evening coz the grass is usually drier by then.
Worst case this time of year is you might hurt the surrounding grass a bit, but it should be fine.