From what I've been able to find I can spray 2,4-D and kill the offending weeds.
HOW to spray is my question.
I have a spot sprayer...but no spray bar. I can build one (seen several videos from people that have done it).
The bottle says something like 2 quarts per acre....how on earth do you figure out how to do that?
I've only ever spot sprayed roundup, like on a fence line, driveway, etc - get the leaves wet and move on. I mix at 3oz per gallon and just go spray.
I assume you catch the flow and measure it over say, 1 or 2 minutes and add in 5 heads (or whatever on teh bar) and then the speed you're driving? Sounds like a word problem from HS...
Will 2-4-D work on the dogbane/pigweed/johnson grass? Add something else to it?
Sounds like you're wanting to spray a hay field and not kill the "hay". Did I read that right?
This is a common problem. Like wanting to kill foxtails in hay -- nothing is selective enough to kill the foxtails without killing the grass hay too.
What is your hay? Typical here is a mix of alfalfa, orchard grass, and timothy, for example.
2-4-D will kill anything with a LEAF. Like alfalfa, clover, broadleaf weeds, etc. It's the classic lawn weed-killer. Won't kill things with a BLADE, like grass.
Roundup / Glyphosate is going to kill everything. It's "non-selective". If your plan is to kill it all and start over, go with Roundup.
I don't see any reason to ever mix Glyphosate with 2-4-D.
If you just want to spray your "hay" and clean up weeds with leafs, 2-4-D will do it but you'll only be left with straight grass hay. However, it won't kill other offending weeds with blades like foxtail if they're a problem. This might be a good plan for you and you could still overseed with alfalfa or some other better quality hay seed later to get a better quality "mixed" hay.
So WHAT you spray depends on what you want to kill and what you DON'T want to kill.
As far as the sprayer, you pretty much need to get your sprayer together and then figure out how much liquid you're putting down per acre. The pump rate, number of nozzles, pressure settings, ground speed, etc. are all variables. My 40 gallon TSC FIMCO special puts out right at 30 gallons per acre with the average ground speed I use. Once you have that figured out, the rest is easy. You'll have to experiment with your final setup to determine the average output per acre.
