So I was considering planting a small area to non gmo soybeans. If I spray the area with roundup how long must I wait to plant the non round up ready beans?
24 hours after ground contact, as I understand it- but I’d be nervous and would want to go longer!
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Straight glyphosate is generally considered to have no activity thru the soil. So you could plant a few days after spraying. But I’m not a trained pest applicator. So go by the label or ask someone who is like maybe the chemical sales rep.
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Soybeans are also somewhat naturally resistant to roundup.
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Plant them and then spray before they come up. Include some prowl or dual or trifluralin for a good start on weed control. Including a burndown with a preemerge package is common practice.
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You can even plant before spraying gly. As long as your beans have not germinated and are growing gly won’t hurt them.
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Yes, roundup naturalizes when it hits soil. Spray anytime before the germinate. You would have to plant them deep if you include prowl.
The real question is; why grow a small plot of soybeans?
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Around here, they spray roundup + 24d (for the resistant weeds) and maybe pre-emergent what two weeks, then plant.
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I’ve used glyphosate as a burndown before planting for various gardening plants. As mentioned glyphosate is inactivated/binds to the soil.
That said I’ve killed some tomato plants (very sensitive to herbicide) by planting too soon after a glyphosate app. I know you aren’t planting tomatoes. Just thought I’d mention it for other readers.
When we used to rent ground to a row crop farmer, he sprayed glyphosate for non-RR crops just before, or just after planting. Didn’t seem to make a difference. The ground shielded the seed from the herbicide.
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I presume you’re doing seeds, so there is no delay needed. RoundUp effects green tissue only (though heavy applications to stems can be harmful). Labels generally says wait 24 hrs or 7 days (depending on application type) before planting live plants. In practice once it’s dry (about an hour) it is safe to plant.
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Got to be extra careful with Roundup around fruit trees! I believe the suggestion in my state is no more than twice a year and not after June.
Here is an article in Good Fruit Grower that discusses the problems some growers have seen:
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Thank you Blueberry for posting that very informative article! I need to subscribe to Good Fruit Grower, but I can’t keep up with my reading as it is.
We are also very careful w/ glyphosate. It’s a good tool, but we’ve killed some trees w/ it. Young trees won’t tolerate any overspray. Recommendations here are no glyphosate after July 15th I believe.
I have to admit, that article is pretty scary, which reinforces caution. Good post.
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Not to jump on the anti-glyphosate bandwagon, but what do people here think about the human health concerns of glyphosate?
I’ve kind moved from the “buncha bs” camp to the “hmmm … mebbe something to pay attention to here” group.
I have two peach trees that looked great last year, but look like they might die this year. I’m very careful with Roundup, so I don’t believe that’s the reason. Probably just PTSL which is a big problem in the South East.
I expect a lot of the damage in the article was a result of spraying the suckers or hitting the trunk with the Roundup. I switch to Glufosinate about the time I see the suckers just to be safe. I hate the fact that it cost about 5X as much as Roundup.
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Mark,
I’ve went back and forth myself but this year I used round up on thistles and don’t regret it. I think every chemical needs to be taken seriously. The purpose of this post is to better educate myself on chemicals such as round up so I can make the best decision I can given the situation. None are good for my health. If I can get out of using chemical reasonably I do.
Thank you to everyone who helped me with the questions I had about round up. The information you provided cleared up a lot up of questions I had. The hardest part for me about chemicals is to understand their intended purpose. I don’t want to spray chemicals as harsh as 24D or tordan for example to kill thistle but many people do. Roundup from my perspective is better for thistle and by everything I read and you’ve said for non gmo soybeans. Tordan is stump killer and 24D is a defoliator so why do I hear people sometimes use them for thistle? Tordan has a long term residual that stays in the ground and kills trees that touch the roots of the trees stump that was intentionally killed. I try to use the minimum chemical I can in all situations and closely match the right chemicals for my needs.
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I would not consider 24-D all that harsh. It is used to selectively kill broadleaf plants by making them grow to death, it will not hurt grasses including corn. It is widely used on lawns to kill weeds. You will be fine using it if you are careful about drift, but grass is my main problem so I don’t use it. I read that citrus farmers spray their trees with a very low dose 24-D to increase fruit size and limit fruit drop.
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Glyphosate is a broad-spectrum herbicide. When spraying a clover field that had some Jujube trees in it, and unexpected gust of wind on an otherwise calm day must have caused enough drift to impact one of the trees. It did not die, but it has had stunted growth ever since.
While Glyphosate is generally thought of as non-selective, it can be used selectively. If you are concerned, rather than using a backpack sprayer to control weeds around fruit trays, one could use a wicking bar. I have a large one that I use to kill weeds in clover fields. I have a large one that I put on the front end loader of my tractor as pictured at the top of this link: Wicking Bar Vendor. This is a very efficient way to use Glyphosate. The selection is done by height. When I want to keep low growing clover but remove taller grasses and broadleaf weeds, I simply adjust the height so the gly is applied directly to the weeds and the clover is not touched.
If you scroll down to the bottom of the link, you will see a small handheld wicking bar. You can make your own if you like. This would be a nice way to control weeds around trees. Direct application means you don’t need to worry so much about wind or overspray.
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I have a few questions about herbicide under trees.
First some background.
Like @blueberrythrill I’ve used glyphosate under trees and also gramoxone (a non-systemic burn down like glufosinate). The problem with the non-systemics is that they don’t last very long - basically just chemically mowing.
However, we’ve killed a few small trees with overspray from glyphosate. We are trying to be more and more careful with it, but the bigger the spray equipment, the harder it is to not get any on any foliage. On young trees we’ve resorted to a hand sprayer this year.
In light of this, I’m considering using something like Stinger (clopyralid) under the trees. I just got through using it in the row middles to clean out the clover. It’s strictly a broad leaf herbicide. My question is, does anyone know if it would be safer than using glyphosate? Most of the weeds which grow under the trees are broad leaf weeds. If grass grows underneath I can use Poast, which is harmless to peach trees. Stinger is very expensive, but if it is substantially safer to the trees, it might be worth it. Blueberry, @c5tiger, @forestandfarm, what do you guys think?
Also Tiger, I was interested in your comment about 2,4-D. Considering Cityman’s experience, do you think citrus trees are just more tolerant of 2,4-D, or do you think that Cityman’s trees just got a really heavy dose?
Forest,
I have a some questions about your wick bar, if you don’t mind. Can you point the wicks straight down to get to really low growing weeds, which would also keep it away from low hanging tree foliage? Also how well do you think it would work on uneven ground? Would it hurt the wicks to get dirty (hanging them straight down they would touch the dirt sometimes? I also wonder if they got dirt on the wicks, if it would be enough to inactivate the glyphosate? How long have you been using yours? And lastly, do you see any problem installing a pressure fitting and filling the pipe continually from a spray tank with a pump, as it doesn’t look like the pipe would hold very much?
A lot of questions I know, but I’ve never talked with someone who actually used a large wick system.
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A wicking bar is essentially pieces of rope that wick gly out of the pipe and wipe it on weeds. The web site I linked shows different configurations. I mounted mine on the bucket plate of my FEL. I can adjust the height dynamically from field to field. For doing field work, I’ve also seen them mounted on ATVs and such. With my large wicking bar, both ends of a short piece of rope go into fittings in the PVC pipe about 6" or so apart. The next rope overlaps the first, so the entire 10’ span has rope. The PVC pipe is rotated so the rope hangs below the pipe. By raising or lowering the FEL, I adjust the distance between the rope and the ground. This may not be the best tool for very low growing weeds. It generally works the other way where the desired vegetation is lower growing than the weeds. Dirt will make gly ineffective. The pipe doesn’t need pressure. Unlike a sprayer where gly is much more highly diluted, with a wicking bar there is much less carrier since it is wiped on weeds. I can do quite a few acres of clover and usually have gly left over in the bar when I’m done. I’ve been using my wicking bar off an on for about 8 years now.
My thought was not to use a large system lime mine around trees. I was thinking more of using a smaller hand-held wicking bar to wipe weeds by hand in that magic 5’ circle around the base of a tree. Since you are wiping rather than spraying I was thinking it would avoid overspray.
If I were trying to kill all vegetation in a field with fruit trees, I’d probably use the hand held wicking bar around trees so I had a buffer zone around the trees and could stay further away with a sprayer. I’d also wait for a dead calm day.
Personally I like a clover base in a field. A wicking bark can handle taller weeds. For grasses clethodim is safer for trees than gly.
Thanks Forest for the info. on the wick systems.
Me too, but clover is generally a disadvantage in fruit tree rows. It harbors stink bugs and invites foraging bees.
Any thoughts on the relative safety of clopyralid vs. glyphosate to fruit trees?