Growing Corn in a Cold Climate

Your guide to growing corn in the frosty regions

Corn is one of the highest yielding crops to grow. Think about it: for every single kernel you place in the ground in spring, you get something like a 600 kernel return on the cob. Perhaps more or less depending on the variety, but a well-grown corn plant will easily put out a ~500x return, pushing up to over 1000x if you get a good second ear. Not bad for a seedy investment! The fact that it's also delicious and nutritionally dense are good reasons for it being a staple crop in much of the world.

Famously, though, it can be finicky to grow, especially in cold climates.

Farmers know what gardeners don't: corn craves heat, and you can measure exactly how much heat any one variety needs and compare that against your climate's averages to check if it's a good idea to plant that variety. On commercial farms where failure is felt by the wallet, I doubt anyone plants a corn variety they don't know the SHU of. In gardens, especially where the garden is grown for fun and not profit or sustenance, I doubt anyone has ever measured the SHU of 90% of the most common varieties. It's certainly an uncommon advertisement. You might know how many days to maturity your seed is, but if the seed came from a big box store or even most of the major garden seed companies, that measurement was almost certainly not taken anywhere near your garden. How do you know how your garden's climate will suffice? If you use a service like Pioneer's GDD calculator you can get a very accurate picture of what GDD your gardens have received in the recent past to give you a picture of what varieties are going to mature for you.

In 2025, I grew a corn advertised as 78 days to maturity. From transplant, it took exactly 100 days to reach maturity in my garden. Tack on another 10 days if you want to account from when I planted the seed in flats. Clearly, the field they measured the rate of maturation in was warmer than my community garden plot. My garden received about 2250 GDD in 2025. If you want the best success with corn you'll also need to give it plenty of water, especially during the most important stages of ear development:

• Ear formation
• silking
• milk stage

You'll also need to pay attention to your soil's fertility, as corn is a very hungry plant. I put 20 pounds of fertilizer in my plot,