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View Full Version : How soon after spraying can I mow?



JackSprats Mom
Aug. 9, 2011, 04:35 PM
So I'm battling fields that were left alone for several years and have a ton of brambles etc.

I've sprayed and I'm wondering how long I have to leave it before I can mow? After the first spraying I left it a week then mowed to try and keep things under control but I don't want to waste the spray if thats too soon :confused:

ThatScaryChick
Aug. 9, 2011, 04:40 PM
I would think you would only need to wait three or four days at the most. Have you tried to do multiple weed sprayings in a row? Like spray, then leave it for a few days, spray again and give it a couple days and then mow?

MeghanDACVA
Aug. 9, 2011, 04:46 PM
Be sure the weeds are dead before you mow. Depending on the herbicide and the weed (type, age) this will vary. Mowing before they are dead defeats the purpose of spraying them.

secretariat
Aug. 10, 2011, 05:36 PM
Agree with Meghan - check the color/appearance. When brown, mow.

phoebetrainer
Aug. 10, 2011, 07:23 PM
Read the instructions on you spray. It should say keep stock off for .....days, or do not graze for ......days or remains toxic for ......days - that is the number of days that the herbicide goes on being absorbed for. As a rule of thumb an dif there is no information, I would leave it 10 days - herbicides on woody plants like bramble are absorbed slowly.

You would have been better to mow first then wait until the growth started coming away again - and then spray. Herbicide is absorbed into new growth more easily, faster and with greater effect than into older plants.

JackSprats Mom
Aug. 16, 2011, 11:21 AM
Thanks guys, I'm using Crossbow which doesn't need any down time for grazing.


You would have been better to mow first then wait until the growth started coming away again - and then spray. Herbicide is absorbed into new growth more easily, faster and with greater effect than into older plants.

You know there are two theories on this, yours (which my DH agrees with) and the other that you should spray full grown plants as it has a bigger surface area to absorb the herbicide.

And yes, I am spraying multiple days. I am expecting it to take another month or so of on and off spraying to get the field under control and then to hit it early spring again.

Guilherme
Aug. 16, 2011, 11:26 AM
IIRC it's the rate of uptake, not the area of leaf covered, that is the critical measure.

I waited six days last time I used 2,4,D on a field. The kill was far enougha long that the vast majority were yellow to brown (even the pig weed and blackberries). I've had no regrowth.

G.

Phaxxton
Aug. 16, 2011, 12:02 PM
I just sprayed today with WeedMaster (2, 4-d and dicamba). We just had a few days of rain that ended a couple days ago, so I am hoping we sprayed at a good time to get them during a growth spurt... I didn't get a chance to bush hog before they came to spray, so I am planning to mow in 10-14 days.

jawa
Aug. 16, 2011, 01:08 PM
I find that if you have a good rain around the time of the spraying the up take of the herbicide it quicker. If the plants are somewhat dormant due to lack of rain, it takes longer for the plant to die.

Add a little Dawn to the herbicide and it will act as a surfactant and allow the herbicide to enter the plant better.

Guilherme
Aug. 16, 2011, 04:45 PM
My quick guess is that real surfactant, properly used, will be cheaper than diswashing liquid, where you have no idea of how much to use. If you use too much you're polluting and wasting money. If you use too little you're just wasting money.

Sometimes just buying the real stuff works out better.

G.