Crop Progress

 

Farmers are making significant progress on planting but some areas are well behind. May 2025 has been the second coldest May on record. Between cold, wet, windy conditions; farmers are managing to get crops planted. Some areas have received over 7 inches of rain, just in the month of May and these farmers are way behind getting crops planted. However; soil microbes, plants, and humans would benefit from more sunlight, warmth, and adequate moisture.

On the weather front, the polar vortex from the arctic region has been dipping down into the Midwest, bringing cold air, wind, and some moisture. La Nina events may be starting to fade, but it’s allowing the colder conditions to persist. Added to that situation, dry conditions in Saskatchewan and Manitoba, Canada are fueling wildfires and smoke which is further reducing sunlight in the USA Midwestern States.

When it is cold, microbes do not reproduce as quickly. Microbes double their population every 10°F increase in temperature above 50°F. These microbes make nutrients available to the plants. Many emerging plants are looking weak due to nutrient deficiencies. A little sun, warm weather, and adequate moisture will allow plants to grow better.

However, many plants are also suffering from cold imbibition which can have a direct effect on yield. Cold imbibition or chilling occurs when the soil temperature drops quickly as the plant seed is taking in water to sprout. A critical time period is 24–48 hours after planting and cold injury below 50°F may occur to the emerging seed and plant by causing cell membranes to rupture. The result is often reduced germination, especially in corn but also soybeans. Sometimes, corn will corkscrew and all plants struggle to emerge when this occurs. Weakened plants hurt by cold imbibition are more susceptible to disease and insect damage.

The colder weather has significantly reduced growing degree days (GDD). Growing degree days (GDD) are defined as the accumulated temperatures that plants and insects need to mature. Most plants grow the best between 59°F at night and 77°F during the day. The range is 50°F to 86°F. Above and below those minimum and maximum temperatures, plants have to expend energy either to stay warm or to cool off. Growing degree days are calculated by an average of the maximum daytime and nighttime temperatures minus 50°F.

Corn needs a minimum of 100 GDD to germinate and about an average of 2700 GDD to reach black layer or maturity. That varies by corn variety and corn maturity. Some corn needs slightly less, others slightly more. Planting early allows the corn to gather more GDD quicker, but in a cold May, it takes longer for that corn to emerge, up to 3 weeks. Later planted corn comes up much quicker (ideally within 3 days) and the corn tends to be healthier. However, it has to make up some GDD and late planted corn requires a little less GDD to mature.

While most farmers have to wait for good weather, there are two nutrients known to help with weather stress, especially low temperatures. Adequate potassium enhances growth and promotes production of the growth hormone auxin. Potassium (K), which is a salt, also enhances the plant’s ability to withstand colder temperatures. Adequate K helps plants survive lower freezing temperatures better in the spring and fall.

The other nutrient that helps with temperature extremes and plant stress is organic silicate. Not considered an essential nutrient, silicate (a form of silicon) is the 7th most common element found in plants. Organic silicate increases the size of the phloem and xylem, the nutrient transportation pipes in plants, allowing them to cope with many types of stress much better. Silicon is everywhere in the soil, especially soil particles (sand, silt, clay); however, to aid the plant it has to be in a specific organic silicate form. Two elements vastly under-researched and poorly understood are silicates (silicon) and magnesium (center element in chlorophyll).

Finally, with a lot of crops planted in slightly wet to wet conditions, the soil is hard and crusted. Many farmers used to rotary hoe or lightly harrow emerging crops, especially soybeans. It’s very tricky. The soybean cotyledon (the first two emerging leaves) are very tender, and if they are knocked off the plant, the soybean plant will die.

Here are some observations from crop scouting. Some corn had not emerged yet after planting it two weeks ago. The ground was hard as a rock. After 0.4-inch rain, about 80% emerged the very next day. This year, a lot of crops are emerging slowly and unevenly, with many fields being partially and even totally replanted. Let’s hope for better weather!