You’re noticing poor stands in your soybean fields. You’re likely questioning the cause, but the most important question you’re asking yourself is this: Should you replant?
Learn how and when to assess plant stands to get down to the root cause (no pun intended) of the problem and how to rectify it. Let’s think through a few scenarios to help you decide whether to replant.
Methods of evaluating soybean stand counts
Ideally, assess soybean stands at the VC growth stage when environmental conditions are fairly stable (not too cold or moist).
Assessing earlier, at the VE growh stage, typically results in underestimating, since some plants will have not yet emerged.
Here are several soybean stand count methods to help you determine your plant population.
Traditional method to determine soybean stand counts
- Measure out 1/1000 of an acre based on your row width.
- Count the number of live plants in the measured area.
- Repeat this process at least five times across the field.
- Average the counts and multiply the average number of plants by 1,000 to obtain the plant population per acre.¹
Alternative stand count methods
The traditional stand count method can prove laborious if you’re planting in narrow rows. In that case, you can use the hula hoop method with a simple multiplication factor depending on the hula hoop diameter to determine your stand count.
Additionally, University of Wisconsin’s BeanCam app uses field samples to calculate expected yield and help you decide if replanting is right for you. Drone imagery can also be helpful in estimating stand counts. Keep in mind that weeds among the soybeans can throw off drone assessments, since their algorithms can’t always tell weeds from soybeans.
No matter which stand-evaluation method you use, always assess multiple, representative field sections, avoiding areas that are too dense or too sparse. The more samples you take, and the larger they are, the more accurate your estimates will be.
Determining the cause of poor soybean stand counts
If you notice uneven emergence, poor seedling vigor, or variable plant spacing, investigate what may be causing the poor stand and determine how widespread it appears to be.
Carefully dig up seedlings and check for the following:
- Seed rots and seedling blights that lead to damping off and seedling death
- Herbicide injury manifesting as stunted growth, leaf discoloration, and stem twisting, with necrotic lesions on the cotyledons and hypocotyl
- Insect and other pest problems (watch for damage from seedcorn maggot, black cutworm, true armyworm, slugs, millipedes, and isopods)
- Soil crusting following heavy rains, especially in soils with a higher clay content.
- Drowned out areas following rains that leave standing water for more than a day, especially in hot and sunny conditions that will speed the depletion of oxygen in the soil
- Planter problems that result in less-than-optimal seed depth, drop and spacing
- Sidewall compaction that damages soybean roots, causing roots to grow horizontally along the seed furrow instead of branching out²
Poor soybean stands often can often be fixed within the season with replanting, but learning how to address problems now can also help you create a proactive management plan for the future.
How to address poor stand in soybeans
High-yielding areas of the field will be less impacted by low plant populations than will low-yielding areas. Soybeans typically branch out and compensate for lower plant densities, so keeping a thin stand may be the most economically beneficial option.³
Here are two options to consider when dealing with poor soybean stands.
Overseeding
If you find pockets that are much lower than 70,000 plants per acre, you can likely correct this with overseeding. When overseeding, established plants will do the heavy lifting, producing the majority of the yield from their mainstem and branch pods. The newer overseeded plants will pull their share, but they’ll primarily produce only from the mainstem.⁴
Most of the time it takes 70,000 to 75,000 healthy and uniformly distributed plants per acre to reach 95% of the yield produced by full stands, but this differs across regions.⁵
Replanting
Soybeans typically don’t require replanting, unless uniform stands are less than 75,000 plants per acre when planted prior to mid-May or under 50,000-60,000 plants per acre when planted late May into June.⁶
Replanted soybeans rarely require seed treatments since soils have already warmed sufficiently, but don’t skip a fungicidal seed treatment if the field has a history of seedling disease. Additional post-emergence herbicide may be helpful, as low or uneven soybean populations are more susceptible to weed pressure since early emerging weeds get a headstart without being suppressed from a fast growing, lush plant canopy.
Replanting recommendations are specific to each field, so talk to your seed retailer, a nearby extension office agent, or your regional BASF representative to understand your options.
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Endnotes
- Anderson, Meaghan, et al. “Stand Assessments - Soybean.” Integrated Crop Management, ISU Extension, 2025, crops.extension.iastate.edu/encyclopedia/stand-assessments-soybean. Accessed 22 Feb. 2025.
- Anderson, et al. “Stand Assessments - Soybean.”
- Anderson, Eric. “Assessing Soybean Stands.” Soybeans, MSU Extension, 13 June 2024, www.canr.msu.edu/news/assessing-soybean-stands. Accessed 22 Feb. 2025.
- Casteel, Shaun. “Soybean Stands: Emergence? Replant?” Pest&Crop Newsletter, 14 May 2021, extension.entm.purdue.edu/newsletters/pestandcrop/article/soybean-stands-emergence-replant/. Accessed 22 Feb. 2025.
- Carleo, Jenny, et al. “Soybean Plant Stands: Is Replanting Necessary?” Soybean Research and Information Network, 2023, soybeanresearchinfo.com/wp-content/uploads/2023/02/20230125_Factsheet_Replant_V2.pdf. Accessed 22 Feb. 2025.
- Anderson, et al. “Stand Assessments - Soybean.”
