Soybean Plants and Potential for Freeze Damage

Over the weekend, temperatures dipped into the low 30s, with some areas reaching 28 to 29 degrees. Immediately after a freezing event, soybean leaves may appear wilted (Figure 1); however, the extent of damage is challenging to predict. We recommend waiting two to three days after the freezing conditions to assess plants.

Figure 1. Soybean plant with freeze damage (less than <24 hours after the freeze event. Extent of damage is difficult to predict shortly after a freeze event. (Photo: May 3, 2026; from central OH farmer)

What does this mean for emerged soybean? At emergence, the growing point of a soybean plant is aboveground and vulnerable to freeze damage. If the plant is damaged from the top to below its cotyledons, the plant will die (Figure 2). If just the top portion of the plant is affected, the plant can produce new leaves from the axillary buds at the cotyledon or unifoliolate node.

 

 

 

 

Figure 2. Soybean plant with freeze damage from top of plant to below its cotyledons, causing it to die.

Although temperatures were low over the weekend, the extent of damage to the plants is difficult to assess just using air temperatures. Reported air temperatures are generally collected five to six feet above the soil surface. Although air temperatures correlate to temperatures closer to the soil surface (near the plant’s growing point), there can be differences. Still air can cause radiant cooling of leaf tissues to occur, which can cause plant tissue temperatures to be lower than the recorded air temperature. Cooler leaf temperatures could also induce dew or frost formation on leaf surfaces leading to the damage commonly observed (Figures 1 and 2).

In our research, we’ve also seen variability in freeze damage based on field management practices:

1. Tillage. We’ve observed a higher amount of freeze damage to soybean plants in no-till fields compared to fields that had been tilled prior to planting (Figure 3). In 2024, the air temperature at the Western Agricultural Research Station (Clark County, Ohio) dropped to 28°F on April 22. In a no-till field, soybean plants were severely damaged by freezing and plant population was reduced to an average of 34,000 plants/acre. In a nearby field, plants were damaged but to a lesser extent and had an average plant population of 50,000 plants/acre. (Both studies had a seeding rate ranging from 140,000 to 160,000 seeds/acre.) 

 

 

 

 

 

Figure 3. Freeze-damaged soybean plants. Planted: March 25, 2024 at the Western Agricultural Research Station (Clark County, Ohio). Low temperature of 28° F recorded on April 22. Greater freeze damage occurred in the no-till field compared to the tilled field.

2. Cover crops. In 2021 and 2022, we conducted a soybean planting date (ultra-early, early, and normal dates) and cover crop (early termination, plant green, none) experiment at Wooster Campus (Wayne County, Ohio). In both years, when soybean was planted ultra-early (April 5/April 6) at a seeding rate of 120,000 seeds/acre, the plant population was reduced to 19,000 to 21,000 plants/acre when there was a cover crop (terminated early or planted green). In the no cover crop treatment, plant population averaged 66,000 plants/acre. In 2021, there was more freeze damage visible in the cover crop treatments (Figure 4).

 

 

 

 

 

 

 

 

 

Figure 4. Freeze-damaged soybean plants. Planted: April 6, 2021 at Wooster Campus (Wayne County, Ohio). Photo: May 13, 2021. Low air temperatures ranged from 32 to 37°F between May 9 to May 13.

3. Plant residue. More plant residue on the soil surface can result in a higher level of freeze damage. Soybean planted into wheat straw residue exhibited a higher level of freeze damage compared to soybean planted on the same day (in the same field) without wheat straw residue (Figure 5). Low air temperatures of 30 to 37°F were recorded five days prior to the visible damage.

 

 

 

 

 

 

Figure 5. Freeze-damaged soybean plants in wheat straw residue (A) and without wheat straw residue (B). Low air temperatures of 30 to 37°F occurred five days prior to photo. Photo credit: Mabel Dwomoh, Ohio State University

We hypothesize this difference may come from the greater residue levels on the soil surface acting like a micro-windbreak at the soil surface. Less air movement near the soil surface could lead to more radiant cooling of plant tissues in those environments, resulting in greater instances of freeze damage.

In addition to field management practices, we also have evidence that freeze damage in soybean may occur differently across varieties and seed characteristics (seed size, seed vigor). Thus, scouting fields is essential to assess damage and should occur after a few days of good weather to assess new plant growth.

What does this mean for soybeans that were planted but not emerged?

Soil temperatures, especially when wet, are much slower to change in the spring than air temperatures. Short periods of near-freezing air temperatures don’t lead to rapid soil temperature changes, and temperatures are also slower to change throughout the day. Recent work also suggests soybean seeds can absorb 35°F water for the first 24 hours after planting, followed by 12 hours at 50°F and still germinate to 85%. This suggests a lot of the damage we see from cold temperatures early is not likely from imbibitional chilling, but possibly due to challenging growth of the seedlings during or shortly after emergence.

A brief cold period is unlikely to cause imbibitional chilling, but will likely slow seedling growth and could delay emergence. Generally 110-130 GDDs have been cited as the needed heat units to see soybean emergence under normal conditions. At low temperatures the plant’s relative growth rates is decreased, which means that gains in growth per day are reduced by even more compared to if temperatures were 5 or 10 degrees warmer. With low daily GDD accumulation, it is likely that more total GDDs will need to accumulate before emergence will be seen because growth is also happening more slowly.

References:

Kannberg, S., Lindsey, A.J., Chiavegato, M.B., and Lindsey, L.E. (2024). Effect of ultra-early, early, and normal soybean planting dates and rye cover crop on soybean grain yield. Agronomy Journal, 116, 1321-1330. Available at: https://acsess.onlinelibrary.wiley.com/doi/10.1002/agj2.21550

Ortel, C., Lindsey, L.E., Casteel, S., Kandel, H., Nafziger, E., Ross, J., Matcham, E., Moseley, D., Preza Fontes, G., and Conley, S.P. (2025). Low soybean plant population: Is replanting necessary? Crop, Forage & Turfgrass Management, 11, e70032. Available at: https://acsess.onlinelibrary.wiley.com/doi/10.1002/cft2.70032

Neththasinghe, N.A.S., de V. Gomes, V.E., Wilson, A., Lindsey, L.E., and Lindsey, A.J. (2026). Influence of cold temperatures during the imbibition phase on corn and soybean germination. Agrosystems, Geosiences & Environment, 9:e70361. Available at: https://acsess.onlinelibrary.wiley.com/doi/pdf/10.1002/agg2.70361