# Best time to apply herbicide?



## RockmartGA

Here's a question for all you scientific types: When is the best time of day to apply herbicide? Early morning? Heat of the day? Late afternoon? Or does it matter?

The reason I ask is that last weekend, I started spraying my fields and had to finish up Monday after I came in from work. So, I'm out there at 8:00 pm spraying and wondering if I'm really doing any good or just wasting money.

Any thoughts?


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## Vol

RockmartGA said:


> Here's a question for all you scientific types: When is the best time of day to apply herbicide? Early morning? Heat of the day? Late afternoon? Or does it matter?
> 
> The reason I ask is that last weekend, I started spraying my fields and had to finish up Monday after I came in from work. So, I'm out there at 8:00 pm spraying and wondering if I'm really doing any good or just wasting money.
> 
> Any thoughts?


I prefer to do my spraying early a.m., but mainly because of light to no wind early. I have sprayed at all daylight hours and have had very good results. Some herbicides can have a volitization problem during the afternoon high temps of summer and early fall in most areas. At those times a good surfactant is very important. There is nothing wrong with spraying in the late afternoon.


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## haybaler101

Depends on which chemistries you are applying. Glyphosates should be sprayed only on dry vegetation or as the dew is drying. They also need sunlight to translocate through the plant and the product needs to dry on the leaves. So spraying glyphosates in the evening with dew and darkness coming or pushing in front of a rain is a waste of time. Some herbicides such as Select are useless if sprayed on wet grass. Atrazine works best if applied in front of a rain to activate it. Best advice is to consult your supplier on each product you intend to apply and if he or she doesn't know, find another supplier.


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## Vol

Rockmart, here is a link for a rainfast chart for the unpredicted thunderstorm or shower when using herbicides. I have applied glyphosate late in the evening(sunset) as a dew was about to settle and had the same excellent results as if I had sprayed at noon.

https://docs.google.com/viewer?a=v&...cBLxcR&sig=AHIEtbQjpXSoug7Z7U1Y76COT84tdWOJjA

Regards, Mike


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