Organic Weed Management in Soybeans
Weed Control in Organic Beans – See the Big Picture
By Sam Oschwald Tilton
OATS Training Specialist and an Organic Advisor at Glacial Drift Enterprises
Published October 5th, 2025
Managing weeds is often the top challenge for organic growers, and one of the main reasons conventional farmers are hesitant to transition. As someone who makes part of my living teaching organic weed management, I am always happy to talk weeds. I’ve found there is a wide spectrum of expectations on what level of weed control is realistic on organic soybeans. Some farmers accept the weeds, finicky harvests, and lower yields that come with them. Some farmers expect a pass with a hand-hoeing crew to walk their beans. Then there are those rare growers who achieve a high level of organic weed control without any hand labor. I love learning from them. I recently had the special treat to hear the deep and complementary experiences of Sophie Rivest-Auger and Matt Sattelberg as guests on an episode of The Organic Advisor Call Series. We talked through a wide variety of weed management strategies they use to control weeds effectively in beans like snap beans, dry beans, and soybeans.
While shiny pieces of metal easily catch the interest of farmers, and myself, Sophie and Matt stressed that the most important methods take place seasons before a soybean seed is ever put in the ground. You can think of weed management as an iceberg, and nice cultivators are important, but they are the shiny tip of the iceberg. Whereas, strategies to reduce the weed seedbank are the much bigger part of the iceberg underneath the water’s surface. Designing a rotation to minimize weeds throughout the season is key. Growing a variety of crops that have tillage, planting, and cultivation at different times helps keep many species of weeds on defense.
Basic agronomy and tillage play a crucial role in setting up beans for success. If soil drainage or pH is off, conditions can favor well-adapted weeds over your crop. Thoughtful tillage can be your friend. For example subsoiling may be called for if a previous crop was harvested on wet ground, because compacted soil often favors weeds over crop. If perennial weeds are a challenge, fall tillage is a good time to disturb weeds like thistle or quack grass and leave them on the surface over winter. Moldboard plowing, though harmful if overused, is an effective weed management tool. Because it buries weed seeds deeply, they often won’t emerge to compete with the following crop. Plowing can be especially helpful in fall tillage when beans follow corn, so the thick corn residue is buried and won’t interfere with bean planting or cultivation. Other tillage implements with discs will cut up and size corn residue so that it doesn’t interfere with the following bean crop.
You can see how the moldboard plow buries most weed seeds below 4 inches. Since most weed seeds only germinate in the top 2 inches, burying them makes the plow a good tillage tool to precede crops that are less weed-competitive.
Source: SARE, “Manage Weeds on Your Farm – Mechanical and Physical Weed Management”
Each tillage tool has its own place in weed management, based mostly on where it puts weed seeds and perennial weed roots in the soil profile.
Source: SARE, “Manage Weeds on Your Farm – Mechanical and Physical Weed Management”
Spring tillage is important for clean bean fields. There can be a few goals in spring, and working the soil deeply is usually not one, because wet soils will preclude deeper tillage. Matt likes to run just shallow enough to erase the tire tracks. Working shallowly will preserve soil moisture for the crop and let farmers get in the field sooner. Another goal of spring tillage is making soil of fine tilth so that clods don’t get kicked around during cultivations, overall soil health plays a role here as well. Farmers can also try to encourage weeds to germinate if they can fit in an extra tillage pass. After an initial tillage pass in spring, Matt sometimes runs the entire field with a tine weeder a few days later or just before planting, in order to kill weed seeds that have germinated before the crop is planted. A good saying here is, “The best time to weed is before you see weeds,” because those tiny newly-germinated weeds are the easiest to kill.
Planting has many opportunities to set up effective weed management. Planting densities are often given for conventional practices, but organic growers want to increase their density and/or narrow their rows so the crop canopies faster to shade out weeds. A higher seeding density than conventional can help make up for crop killed in cultivations. "Our thought is, if there's not a bean there, there's going to be a weed there," Matt says. Planting a little deeper can be helpful, as it gives more time and space for a blind-cultivation pass before the crop emerges. Timing is crucial. The goal is that your crop jumps up out of the ground, and part of that is waiting to plant until soil temperature is ideal for your variety. Some farmers will also delay planting so that problem weeds germinate first, giving the opportunity to kill them with a shallow tillage pass before the planter comes through.
After planting, the race is on. Blind-harrowing with a tine weeder or rotary hoe can happen just a day or two after planting up until hook-stage. In the age-old debate between rotary hoes and tine weeders, we can say that rotary hoes are better when the soil is crusted or there’s more residue, whereas tine weeders work in softer soil and provide some leveling. When the beans hook, it’s time for caution. Most farmers try to stay out of the field, but you can get in with a soft tine-weeding or a flame weeder. After hook-stage you can really have some fun, because beans can take a beating and seem to yield better when they are beaten up. Tine weeders can be used aggressively until flowering. As with all organic cultivation, expect to kill a small percentage of your crop to be aggressive enough in your cultivations.
"Some farmers are too afraid to hurt the crop. Just plant a lot of population and make sure that when they are very young you destroy a percentage at each pass. So you're sure that you're hard enough on the weeds."
– Sophie Rivest-Auger
In the cultivation timeline, after the rotary hoes and tine weeder comes the row-crop cultivator.
European-style cultivators can’t handle as much residue, but they are great at moving very little soil. This allows farmers to cultivate earlier without fear of burying the crop.
Camera-guided cultivators are accurate, easy to set up, and allow higher speeds to cover more ground in tighter weather windows.
Finger weeders, once the beans are well-rooted, can be used through the final pass. These have been a game-changer because they reach into the row and uproot weeds.
A helpful way to think about the progression of cultivation in-season is looking at how you are moving soil. Using different cultivation tools we can move soil into the row to bury weeds, then rip those hills down with tine weeders or finger weeders, and vice-versa. Soil can be moved back and forth throughout the season to keep weeds from taking hold.
"Do what you're comfortable with for crop damage, and then do one pass where you're uncomfortable, and where it looks like you're just turning the field black. Give it some time to recover and 90% of the time those beans will. And you’ll say, man, I'm going to go that aggressive next time over the whole field… but then there's always that one time where you go too hard, and you really wish you didn't!"
– Matt Sattelberg
Practicing weed management throughout the season is crucial to clean beans—from planning the rotation and addressing basic agronomy, to fall and spring tillage, to planting and cultivation. But more than that, Sophie and Matt stress that the organic farmer’s mindset is crucial. You’ve got to be comfortable with a certain amount of discomfort as you practice a higher level of crop disturbance to kill weeds. It takes patience as you learn about new weeding tools and test them in different conditions to find the best settings in your soil and weed species. Observation is key, because you have to scout each field to know when the soil crust is perfect, or just before your beans break the surface, or as soon as the crop is big enough to finger weed. Eliminating hand-weeding isn’t easy, but it is possible when all the pieces come together.
Want to hear the full conversation with Sophie and Matt?
Watch “Organic Weed Management in Soybeans” from our 2025 Organic Advisor Call Series on YouTube.
Listen as a podcast for a closer look at managing weeds in organic soybeans.