Hoorman: When to start planting
Its Mid-April and as May approaches, farmers are gearing up for planting season. Early planted crops generally have a yield advantage over late planted crops. Most crop yield is related to moisture at pollination in both corn and soybeans. Good yields are possible if there is adequate summer moisture. Usually, July rains have a big impact on corn yields, while August rains have more of an impact on soybean yields.
There is about a 3-week window in Ohio for optimal planting. In Southern Ohio, April 10-May 10, and in Northern Ohio April 25th and May 10. For crop insurance coverage, May 5 in southern Ohio and April 10 in northern Ohio. Planting after May 10, on average, results in about a 0.3 percent yield loss per day when corn planting is delayed and by the end of May, this loss increases to 1 percent per day. However, it pays to plant when weather and soil conditions are fit. Mudding crops in can be a disaster if it gets dry. Shallow rooted crops in compacted soils often result in poor crop stands and low yields.
What crop should be plant first, corn or soybeans? The answer is that both corn and soybeans have a similar planting window. Corn is often planted first, because corn is sensitive to moisture at pollination. The growing point on corn is below ground until V6 (six true leaves), so corn is tolerant of frost more than soybeans. Early planted corn benefits more from June and July rains. Since soybeans are indeterminate in their pollination, soybeans tend to be a little more resilient to dry weather. Dry weather still hurts soybeans yields, but soybeans bloom over a longer period of time. Ideally, both corn and soybeans should be planted at about the same time to obtain optimal yields. Many farmers will have several rigs planting at the same time to get their crops planted in a narrow optimal time frame.
Ideally soil temperatures should be above 50 degrees F to plant corn. For Columbus, when Lake Erie water temperatures are 45-48 degrees F, this translates into soil temperatures around 52-53 degrees F. Ideally, check the soil temperature at 4 inches deep. Early planted crops can either have a more active roots system to survive poor spring weather or they can get really stressed from long periods of cold wet soil conditions. Planting deeper helps corn emerge a little slower, but the kernels tend to emerge more evenly. Soil temperatures and moisture tend to be more consistent deeper in the soil which aids in uniform emergence.
While early planting of crops may be optimal, it does not always happen. Yields on late planted crops (End of May to early June) are quite variable. In a dry year, yields can nose dive. However, it’s also quite possible to have average or even above yields if there is adequate moisture. In 2024, a hot dry June hurt yields but July and especially August rains helped improve soybeans yields.
The biggest variability in crop yields occur when crops are planted past the optimal time period. The yield spread increases dramatically the later the planting date with yields ranging from 62-100 percent of average 5-year yields. Good crop yields are still possible with adequate summer moisture and ideal weather. However, dry weather usually spells disaster. The best way to increase crop yields is to have resilient soils by increasing your soil health so that planting delays become less critical.
What affect is the weather having on weeds? Henbit and purple nettle are broadleaf weeds that are blooming, putting on seed, and growing quite rapidly. In wheat and cover crops fields where you want to kill the weeds but let the other crop grow; Harmony, Osprey, and Power Flex many be options for terminating some of these weeds. Weedone (24D) can be used on oats and small grains but there are restrictions on plant height and application rates. Sharpen herbicide applied at low rates has been effectively used to kill many troublesome broadleaf weeds and has less planting restrictions than Weedone (2-4D) on corn and soybean fields. Weedone is very effective for fall applications to clean up marestail and waterhemp and other fall annuals while Sharpen is slightly less effective in the fall, but Sharpen is commonly used during the growing season.
For wheat and cover crops, the warm weather and moisture is making them both grow. If it is wet, letting cover crops grow can help soil dry out. It is starts getting to dry, terminate the cover crop. For wheat, wheat grows best from 60 degrees-80 degrees F. Warm wet weather promotes head scab. Cold wet weather promotes powdery mildew and Septoria. Enjoy the spring weather!