Should soybeans be planted before corn? Probably not, but we encourage you to consider planting soybeans as early as possible.

In South Dakota, our first planting date for crop insurance for corn has been April 10, but for soybeans it’s been April 26. In southern Minnesota and Iowa, it’s been April 11 for corn and April 21 for soybeans. In most of Nebraska, these dates are April 10 for corn and April 25 for soybeans.

We have had many questions about planting soybeans earlier than the first crop insurance date, but we can’t recommend that in good conscience. Sure, some people have talked about amazing soybean yields when planting in early April, but the frost risk is great, especially when you forgo crop insurance.

There is an amazing website I want you to check out every single spring from now on: @mygeohub.org/groups/u2u/purdue_gdd

On this website, for most areas in the U.S. you can zoom in on your area and then make projections for corn hybrid maturities. It will show you what the odds are your crop will make it before the frost in the fall, depending on your planting date. In addition, you can check the box to see the last frost dates in the spring. You can even change the “frost” temperature, so if you want to see when your last frost has come each spring based on 26, 28, or 30 degrees, for example, you can. This will help you gauge whether you want to take that risk in trying some extra-early soybean planting.

Part of what may change your thinking in terms of planting soybeans before corn is Hefty Brand 40 Series Corn. Since you can now plant corn when the soil temp is only 40, we would encourage you to do that with our 40 Series Corn, but we still want you to plant your soybeans early.

Here are three key steps for success with early planted beans.

1. USE A GREAT SEED TREATMENT!

Many of the things that are helping our 40 Series Corn thrive in cold soil temps are included in Hefty Complete Soybean Seed Treatment. Plus, when you treat Hefty or Zinesto soybeans with Hefty Complete, we give you free replants and up to two free resprays for certain insects. Please talk to a Hefty agronomist for complete details on our program. If you don’t use a great seed treatment, we absolutely do not advise you to plant your soybeans early. When planting early, your beans will be under attack from disease much more than normal, and the beans will sit in the ground longer than usual, meaning insects and other pests have more time to damage them prior to and upon emergence.

2. MAKE SURE THE COLD GERMINATION PERCENTAGE IS HIGH OR AT LEAST RELATIVELY HIGH.

If not, plant the soybeans just a little bit thicker. The standard cold germination score in our industry is 80%. If you start with 140,000 seeds per acre, that means you will have a final stand of just 112,000, and that’s if everything else goes right. It is very common to see early-planted soybeans with just a 70% final stand, so keep that in mind.

3. DON’T MUD IN YOUR SEED!

I know you want to go as early as possible. We do on our farm, too, but there’s a limit to it, and that limit is wet soils. If your soil isn’t dry down to the depth you will plant at and just a little bit below that, we encourage you to wait as long as you can so the soil can dry out. With soybeans, planting at a depth of 1” to 1.5” is perfect, and that is much more shallow than corn. It is possible soybean planting might work for a couple days before the ground is truly fit for corn, since corn gets planted deeper, so this could allow you to put some beans in while the corn fields sit.

The number one question people ask is, ‘How much yield can I gain by planting my soybeans early?’
That really varies, but keep in mind all the old planting date studies are missing two things: high yield and a fantastic seed treatment. When you are talking 40-bushel yield potential and no (or poor) seed treatment 20 years ago, that definitely lowers the yield advantage to early planting. Personally, I feel on average in our region we are probably giving up a third of a bushel to maybe half a bushel per day when our soybean planting date goes past May 5, but every area and every year will be a little different.