Fall Weed Control

Fall is a great time to control perennial weeds. Monsanto has a good page on it. They are the devil, but nobody knows more about glyphosate. http://www.monsanto.ca/solutions/postharvest/index.shtml
(Next I learn how to put that window behind a word.)
Our custom machines do from 2500 to 5000 acres a year post harvest. My clients do 2000 or 3000 with their own rigs. I scout every field before without fail, and check about 2/3 post for control. We have great luck with it. Our rules are simple:

1. A little frost is OK. - Stop and wait after -5 celcius or lower. Things might come back, but make sure
2. Growing (regrowing) plants - Juice in the grasses, new tufts of growth on the thistle. Wait a week or more after harvest
3. Clean plants - Wait for heavy dew or any rain to wash harvest dust. If you raise dust when you kick a clump of grass, hold off!
4. We wait for sunlight and 10 celsius - We start at 10am and shut down at 5pm. (Monsanto says 8 celcius any time in the day. I'm more careful.)
5. Dandelions and Canada Thistle - we use 1.25 litre/ac. origonal Roundup (sometimes with just a hint of 24-D, $.50/acre worth). We differ with recommendations on this.
6. Quackgrass - We use 1 litre/ac. (Sod needs more and more next spring)
7. Foxtail Barley - We use at least 1.25 litre/ac.. We use 10 gallons of water hoping to get down to growing points and into the thick tufts. We don't promise much. If you get 70% you are doing great
8. We expect good control on quack grass (80 to 90%), 80% at best with Dandelion and Canada Thistle, 50 to 70% on Foxtail barley and sometimes nothing. and if you get Sow Thistle it's a bonus.

Last things:

• Remember all the different formulations of glyphosate. I'm talking the old formula here
• Careful mixing different companies products. We think we made water on 140 ac this year. Some are different salts.
• We tried some Express/Roundup this year on Dandelions. It looks good 7 days in. We will see in spring.
• Generic or brand name, Origonal or the new Tide, they are all basically the same. We find ourselves still with Monsanto (mostly) either generic or brand name. Monsanto has the most product knowledge and the best performance policy for us