In the last two weeks I have been asked one thing constantly.

Is it too cold to spray?

Well if we are below zero every night then yes. I know that this is a problem right now but we also have to look at what we are trying to get rid of.
When it comes to perennials like a dandelion then we have to use the rule of thumb “if it is below zero then we need two days of plus 10 or greater before we can spray”. What happens is we get some minus temperatures then we get a real nice day and of course when it is nice there is no wind. So what do we do, we jump in the sprayer and start spraying like crazy to catch up. Now with the products like PrePass and Express Pro that have residual we think that they will be our saving grace or silver bullet but remember if the plant is not actively growing you are putting all of your eggs in one basket. What I mean is that if the plant is growing you are getting two modes of death. Through the leaves and absorbing through the roots. If it is not active then you are hoping that you will kill the plant by roots. With annuals and volunteer canola that will work to some degree but with things like dandelions and narrow leaf hawks beard that could be a wreck waiting to happen. So my advise is to wait till we get away from freezing at night and do the proper spraying job the first time We know what happens when we don’t get a good kill on those weeds because it tends to bite us in the you know what and costs us more money to get rid of a simple problem.

Those are my thoughts,

Garth Donald C.C.A.

4 thoughts on “Do Your Weeds Still Have Their Winter Parka’s On?

  1. Everyone has a different idea…

    My dad called a chemical company about their glyphosate and asked (with no liability to the company) what the practice should be. They said 8 degree daytime temperatures for at least a few hours after application. They said freezing temperatures are less of an issue than getting to a warm daytime high to allow the plants to absorb the chemical.

    Basically, follow any advise that lets you spray more, sooner ;).

  2. I agree, unless plants are actively growing you are not getting full efficiency from your product. Daytime temperatures do have an affect, but night time freezing temps will put those weeds into defense mode. Unless daytime temps are warm for a couple of days, the weeds will not resume active growth.
    In addition, with cold temps com ecold soils, so we are seeing a lot more seed treatment going into the ground this year. Just a thought that traditional non-users might want to consider if they want to get in the fields earlier.

  3. Too Many times growers try and push the spraying window and it has dramatic affects on the glyphosate performance. Crop Protection products are expensive and you need to at least follow common sense when spraying.

  4. I have never understood the mentality of spraying when knowledge tells the user not to. I have told more than one grower to not bother putting the herbicide in the tank if he is going out to spray, because he can at least save that money rather than throw it away by spraying.

    All for the sake of putting tracks in the field. Just to “Get it done”.

    I had a grower call me and ask if he could spray one morning. I told him no, it was very cold last night, give it a day. he called the customer service line who told him the same thing, and then called the dealer, again the same answer.

    He went ahead and sprayed anyway, and was surprised he didn’t kill the weeds. Of course it came back as a complaint.

    There should be a psychological study done on growers around spraying. I have had more than one guy tell me “I knew I shouldn’t have sprayed, but the wind was down.”

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