By Craig Allaman, Lead Agronomist, Cornelius Seed 

With the amount of rain we’ve received across the Cornelius Seed footprint, growers may be seeing an unusual late-season issue in both corn and soybeans: seed beginning to germinate before it ever leaves the plant. 

In soybeans, we’re seeing reports of pods splitting and seeds beginning to sprout inside the pod.

In corn, kernels can begin sprouting directly on the ear, a condition known as vivipary. 

While it can be alarming to find a soybean or corn seed already germinating before harvest, the weather conditions leading up to harvest can create the right environment for it to happen. The biggest thing growers can do now is scout fields, identify where the problem is occurring and adjust harvest priorities accordingly. 

Soybeans: Pod Splitting and Seed Sprouting 

Pod splitting and seed sprouting in soybeans have been reported more frequently in recent years. According to Science for Success, these issues are generally associated with stressful environmental conditions as soybeans approach maturity particularly a period of drought or dry weather followed by extremely wet conditions. 

When soybean pods and seeds develop under stressful, dry conditions and then receive significant moisture during seed fill, seeds can expand rapidly. In some cases, that expansion can cause pods to split open. Once the seed is exposed to continued moisture, conditions can also become favorable for germination. 

Sprouting is especially associated with extremely wet conditions after the crop reaches maturity and seed moisture has declined, although sprouting has also been reported near the completion of seed fill around R6. 

What should growers do? 

Unfortunately, there isn’t much that can be done to reverse pod splitting or sprouting once it begins. 

Timely harvest is the best management tool. 

Scout soybean fields now, especially fields that experienced significant stress earlier in the growing season followed by the recent wet weather. If you find split pods or germinating seeds, consider moving those fields higher on the harvest priority list.

As affected soybeans dry, sprouted or damaged seeds may fall from the pods, and the condition can contribute to reduced seed quality, lower test weight or increased foreign material. Combine adjustments may also help remove some lighter, damaged seed during harvest. 

Drying and storage: Check the moisture of affected loads rather than assuming they are dry because the pods look ready. If you plan to store commercial soybeans, dry them to 13% moisture or less. Beans harvested above 13% need a drying plan, and wet or damaged beans require close attention because their safe storage time is shorter. Natural-air drying may work when conditions and airflow are suitable; cool, wet weather may require supplemental heat.

Be gentle with soybeans in a heated dryer. Iowa State University Extension recommends limiting drying-air temperature to 130–140°F for commercial soybeans to reduce cracking and other damage. Aerate to remove heat after filling the bin, then check moisture and grain condition regularly. If you find heating, mold or an off odor, address the grain promptly. Drying can help preserve the remaining grain, but it cannot repair a seed that has already sprouted.

It’s also important to remember that this is primarily an environmental issue not one that a late fungicide application will correct. Research summarized by Science for Success has not shown a benefit from late-reproductive fungicide applications for preventing this type of pod or seed quality damage. 

Corn: Premature Kernel Sprouting or “Vivipary” 

Corn can experience a similar phenomenon. 

Vivipary is the premature germination of corn kernels while they are still attached to the cob. It is most likely to occur when relatively dry, mature corn particularly grain below approximately 20% moisture is re-wetted during warm conditions. 

Think about what has happened in many fields recently: corn has been progressing toward harvest moisture, and then repeated rainfall brings moisture back into the ear. 

Upright ears can capture rain inside the husk, keeping kernels wet. That’s why sprouting is often found near the butt of the ear, where moisture can collect. Corn that is lodged or has ears close to the wet soil surface can also be at greater risk. 

Premature sprouting can also occur alongside ear molds or physical kernel damage. Purdue notes that some ear molds can interfere with the hormonal balance that normally prevents kernels from germinating prematurely. 

What should growers do? 

Again, harvest timing becomes the primary management decision. 

If you find significant kernel sprouting, consider prioritizing those fields for harvest. The concern isn't simply how the ear looks today. Significant sprouting can reduce grain quality and create additional challenges with drying and storage, including greater levels of broken corn and foreign material. 

Drying and storage: Don’t leave heavily affected corn wet in a wagon or bin while waiting for it to dry on its own. Dry it promptly. Purdue University notes that drying sprouted corn at higher temperatures can stop further seedling growth; the appropriate setting depends on your dryer and the grain’s intended use. Nebraska Extension recommends drying affected corn to 14% moisture for storage.

Scout Now and Adjust Your Harvest Plan 

After the recent stretch of wet weather, don’t assume every field should be harvested in the order you originally planned. 

Take some time to walk fields before the combine gets there. In soybeans, open pods and look for splitting, exposed seed and seeds beginning to germinate. In corn, pull back husks particularly on upright ears and inspect the butt of the ear for sprouted kernels. Pay additional attention to fields with lodging, ear molds or other late-season stresses. 

Finding a few affected ears or pods doesn't necessarily mean the entire field has a major problem. The frequency and severity across the field are what should help guide your harvest decision. 

The crop has already dealt with plenty of weather this growing season. At this point, timely scouting and harvest management are two of the best tools we have to protect the grain that's out there. 

If you're seeing sprouting corn or soybeans in your fields and aren't sure how severe the issue is, contact your Cornelius Seed representative or agronomy team. We can help you evaluate what you're seeing and determine where that field belongs in your harvest plan. 

Plant It. Profit. 

Additional Resources 

• Issues with Splitting Pods and Sprouting Seeds in Soybeans — Science for Success
• Storing Soybean — Iowa State University Extension
• Storing, Drying and Handling Wet Soybeans — University of Minnesota Extension
• Premature Corn Kernel Sprouting (aka Vivipary) — Purdue University
• Why Are Corn Kernels Germinating on the Ear? — Nebraska Extension