By Brian Hefty

Cold, wet soils often spell doom for seed germination and seedling health. Look at the below chart based on average weather on our farm and the number of days it takes until corn should emerge based on planting date. This is assuming each corn variety requires the average of 100 GDUs to emerge.

Planting Date Days to 100 GDUs Chart

As you can see, we would have to plant after May 14 if we want our corn to sit in the ground for less than 10 days! Our goal each year is to start planting corn around April 10 (first crop insurance date) and have corn planting done before April 30. That seed must sit there a long time!

Fortunately, there are things you can do to help your crop overcome these issues. Sure, it would be great if you could wait to plant until the soil warms up to a balmy 55 or 60 degrees and never have that soil temp drop below that level, but late planting usually hurts yield and net profit. In addition to doing a great job with your planter, here are a few things we have found increase seed germination, speed emergence, and/or leave a young corn crop in the best state possible.

  1. In-furrow fertilizer. Here’s the key: don’t get too much salt near the seed. We often see a germination decrease and corresponding stand loss when fertilizer rates are too high. How much is too much? That will vary dramatically based on rainfall, soil type, amount of fertilizer landing directly on the seed, heat, and other factors. Our general rule is not to exceed 5 pounds of salt per acre. That equals 3 gallons of 10-34-0 in a 30” row. If you aren’t sure if this is an issue for you, just shut your fertilizer off in a couple spots while planting. Mark those spots, and then check the stand as emergence is occurring. The last thing we want is to spend money on fertilizer and have the fertilizer hurt our crop. Our suggestion is to use low salt products at low rates blended with water. We like Pro-Germinator and Sure-K. These products have helped early emergence in cold, wet soils.
  2. Good manganese levels. On a Midwest Labs DTPA soil test, we want to see 20 to 40 parts per million. Poor manganese levels often lead to uneven emergence, up and down ear placement, and lower yields.
  3. Headline or another strobilurin fungicide in-furrow. Our testing has found that using in-furrow fungicide hasn’t paid a good return when soils are warm and dry at planting and remain warm and dry afterwards. However, when planting early, this is part of our standard treatment. In cold and/or wet soils, disease issues seem to be worse, and whether it’s that or the plant health benefits, all I know is we’ve gained yield.
  4. Insecticide in-furrow or in a T-band. Early season insects, including seed corn maggots, seed corn beetles, wireworms, grubs, and many more can ravage your stand. The good news is insecticide continues to come down in price. While we prefer dry Force or Aztec on rootworms, liquid Capture is very good on many of these “secondary” pests that attack your young corn.
  5. QuickRoots. I know. You may not believe in natural or biological products. Here are 3 ways we try to prove out whether natural products work or not in side by side tests, and I suggest you do the same.
    • Visual observations throughout the season, but especially early on. We have found QuickRoots slightly speeds emergence.
    • Plant tissue testing. We have found QuickRoots treated plants have higher nutrient levels in tissue tests, especially early on.
    • Yield. This is what it ultimately comes down to, but make sure you look closely. A 4-bushel difference that would more than double your money won’t show up on your yield map in 250-bushel corn.
  6. Nutri-Cycle. Another natural product, this one has more than 20 different beneficial microbes. Here again, we have found this product helps emergence and early vigor, which is likely why our tests have shown a really good yield gain, on average. Nutri-Cycle IF is the in-furrow version, and the seed treatment option is Nutri-Cycle ST.
  7. Intego fungicide. In our opinion, this is the best seed treatment fungicide that has come out over the last few years. Intego is the best pythium product there is, and pythium is often the number one disease in cold, wet soils.

I know this is a lot, but I also know that by investing a few extra dollars to protect and enhance the corn seed and seedling, we’re seeing much better early season stands in cold soils, and this is leading to higher yields and more profit in the fall. If you don’t want to invest anything extra, we strongly encourage you to wait until soils warm up to possibly even 55 degrees before you plant. Yes, late planting will likely not yield as much as early planting, but if you lose stand or your seedling isn’t super-healthy following early planting, that hurts yield, too.