Harvesting Wet Soybeans: Considerations and Practical Tips

Unpredictable weather patterns can make harvesting soybeans a challenge for Midwest growers, and wet periods during the fall often push back harvest dates. When conditions for harvesting are less than ideal and you can’t wait any longer for drier weather, the only solution may be to harvest wet soybeans. While harvesting wet soybeans isn’t ideal, with the right tools, timing and drying practices, you can still protect your yield and grain quality.

Factors to consider when harvesting wet soybeans

Soybean maturity

If a late harvest is on your horizon, you’ll want to prioritize harvesting soybean varieties with the earliest relative maturities. These early varieties will dry down first, allowing later varieties the appropriate time needed to reach full maturity.

Soybean moisture at harvest

For optimal harvest quality and storage, soybeans need to be harvested at moisture levels between 14 and 15%. Harvesting at greater than 15% moisture will significantly reduce yield quality and create storage issues.1 Even though soybeans can be dried down post-harvest, there’s a risk that seeds will become cracked or damaged if aerated or dried down improperly.2

Fungal growth

Soybeans that are mature but still wet create ideal conditions for fungal growth, potentially leading to mycotoxin production and reduced grain quality. Any molding that has happened in the field will ruin the storage life of your soybeans. When harvesting wet soybeans, it’s recommended to aerate and dry with low heat and then send to market as soon as possible.

However, any signs of discoloration or surface mold can give you a Total Damage grade at the elevator or processor.3

Mechanical damage

Avoid harvesting soybeans with a moisture level above 18%, because even though they can be harvested at this moisture content, threshing can be hard on the seed. Many more beans are crushed and damaged when the moisture content is high, reducing your yield and quality.4

Drying and storage

There’s a good chance that your soybeans will need to be dried and stored after harvest, especially if you harvest above 15% moisture. Check with your elevator or processor in advance to know their maximum allowable moisture level. If they don’t accept high-moisture beans, you’ll need to manage drying on-farm. Just remember that drying soybeans too quickly can crack or damage seeds.

Practical tip to minimize soybean harvest moisture risks

Adjust combine settings

When harvesting wet soybeans, fine-tuning your combine can reduce damage and losses. Start by reducing rotor speed and increasing concave clearance to prevent cracking. Adjust the cleaning shoe by opening sieves and boosting airflow to improve the separation of pods and debris. Additionally, make sure to slow the ground speed to 2–3 mph, which gives the machine more time to process wet material efficiently.5 These adjustments help protect grain quality and maintain throughput under less-than-ideal field conditions.

Monitor soybean moisture at harvest

You’ll want to keep an eye on the moisture content of your soybeans during the standard harvest window. Harvesting can begin when the moisture levels are around 14-15%. To ensure your moisture tester is accurate, check it against your grain buyer’s moisture meter. Test three separate samples to ensure you are getting the same results.

Time your harvest for optimal soybean harvest moisture

Timing your soybean harvest can make a big difference in preserving yield. Soybeans tend to dry out during the day and reabsorb moisture overnight, so late morning is often ideal. It’s best to harvest after the dew has lifted but before conditions get too hot and dry. If your moisture readings are already low, avoid harvesting in the mid-afternoon, when shattering is more likely. Harvesting at the right time helps minimize pod loss and protect grain quality.

Use appropriate equipment for harvesting wet soybeans

It’s been reported that 80% of harvest loss originates at the header.6 Using flexible cutterbars and automatic header height control can keep the header close to the ground, which is essential for capturing low-hanging pods, particularly in fields with short soybeans or low plant populations.

Consider using draper heads or air-assisted reels to extend your harvest window by a couple of hours.7

Implement proper drying and storage

Proper drying and storage are essential after harvest. If soybeans are coming in at 14–15% moisture, dry them gradually to 12–13% for safe, long-term storage. Rapid drying can crack seed coats, while under-drying raises the risk of spoilage. Use aeration to manage temperature and moisture evenly, and monitor stored grain regularly to catch any issues early.8 These steps help preserve quality and protect your investment through the storage season.

Stay proactive by monitoring moisture levels closely, adjusting your equipment, and planning for proper storage. Don’t overlook these seemingly small decisions that can make a big difference when conditions are working against you.

Experts are available to help you make your decisions. Reach out to your seed retailer, a nearby extension office agent, or a seed company professional like your regional BASF representative.

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Endnotes

1. “Managing Soybean Harvest Timing, Moisture to Improve Yield.” CropWatch, University of Nebraska–Lincoln, https://cropwatch.unl.edu/managing-soybean-harvest-timing-moisture-improve-yield/.
2. Buschermohle, Michael, and Sam McNeill. “Tennessee Soybean Production Handbook: Chapter 10 – Harvesting, Drying, Handling and Storing Soybeans.” University of Tennessee Institute of Agriculture, Oct. 2023. https://utia.tennessee.edu/publications/wp-content/uploads/sites/269/2023/10/PB1912J.pdf
3. Hurburgh, Charles R., Steve Johnson, and Meaghan Anderson. “Managing Wet Soybeans in a Late Harvest.” Integrated Crop Management News, Iowa State University Extension and Outreach, 18 Oct. 2018, https://crops.extension.iastate.edu/cropnews/2018/10/managing-wet-soybeans-late-harvest.
4. Hurburgh, Charles R. “Soybean Drying and Storage.” Iowa State University Extension and Outreach, Nov. 2008. https://www.extension.iastate.edu/grain/files/Migrated/soybeandryingandstorage.pdf
5. Staton, Mike. “Reducing Soybean Harvest Losses.” Bulletin E3487, Michigan State University Extension, 28 Sept. 2023, https://www.canr.msu.edu/resources/reducing-soybean-harvest-losses.
6. Morris, James, Jason Hartschuh, and Elizabeth Hawkins. “Is a Late Soybean Harvest in Your Future?” Agronomic Crops Network, Ohio State University Extension, 8 Oct. 2019, https://agcrops.osu.edu/newsletter/corn-newsletter/2019-34/late-soybean-harvest-your-future.
7. Staton, Andresen, and Singh. “Reducing Weather Risk in Soybean Production.”
8. Buschermohle and McNeill. “Tennessee Soybean Production Handbook…”