All about how to grow popcorn: one the absolute funnest things I grow in my garden every year! Homegrown popcorn is not only colorful and delicious, but unwrapping each ear feels like opening presents on Christmas morning.
I didn’t start out as a great popcorn grower though. My first couple years I only got spotty, ugly ears… now I grow a ton of incredibly beautiful popcorn every year! I’ll tell you how! I’ve even been breeding my own variety called “Midnight Purple Popcorn.” :)
To see what else I’m growing, follow me on Instagram (click here!).
When to plant popcorn
Popcorn typically takes the entire season, so plant it as soon as you can after the danger of frost has passed.
For me in Zone 4 Wisconsin with a last frost date in mid-May, I usually plant corn during the last two weeks of May. I watch the weather and plant on the early side if it’s warm and later if cool. On a cold year, we sometimes plant the first week in June. Corn seeds will germinate best when the soil is 60°F or warmer. If the soil is too cold it has a higher risk of just rotting instead of sprouting.
Corn is one of the few crops that is not recommended to start indoors or in pots. It is very difficult to transplant successfully, so unless you are experienced, directly sow it in the ground.
Karl’s 94-year old grandpa (who has been farming his entire life) says that you “plant corn when the oak leaves are the size of a squirrel’s ear.” He’s been planting corn for a looong time and knows a thing or two about how to grow popcorn!
How far apart to plant popcorn
For best pollination, plant corn in a grid rather than long rows.
For example, if you have 100 seeds to plant, it’s much better to plant 5 rows of 20 than 2 rows of 50.
Plant corn seed about 1-inch deep in the soil. We plant popcorn 10-inches apart in the row, and the rows are spaced 2 feet apart.
We hoe a row, drop in the corn, then cover it up. I find that when I use good, fresh seed and plant when it’s warm enough, I always have good germination. I don’t usually over-plant and then thin.
It’s also important that you plant *enough* popcorn plants. Aim for a minimum of 20. This will ensure there is plenty of pollen floating around and you’ll get good pollination and nice full ears.
Avoiding cross pollination in popcorn
Cross-pollination can cause your popcorn to not pop.
This is important for learning how to grow popcorn: for most crops, cross pollination doesn’t affect the plants that are growing right now in your garden, but only the seed you might save from them and grow the following year. Corn is different. If pollen from a different type of corn pollinates your popcorn, it will affect your crop this year.
When corn is ready to be pollinated, it sends up its tassel. At the same time it starts developing immature ears that expose their silks. The pollen is produced on the tassel and is blown by the wind down on the silks. Each silk is connected to one corn kernel. Each silk has to get pollen on it to form a full ear of corn.
If you are growing popcorn and there is sweet corn or field corn nearby, and that corn is releasing pollen at the same time your popcorn is, your popcorn can be affected and will likely not pop well.
To prevent this, experts say to keep different corn types ½ mile apart— this is the gold standard. You can typically get away with less though. I plant sweet corn in one garden space and popcorn in a different space. These are about 300 yards away and separated by our house and some trees, and that has always worked well for me.
There are other techniques you can use, like covering the silks and hand pollinating them, or growing different types of corn that tassel at different times… but these are very advanced practices.
Watering & weeding Popcorn
The general recommendation is that popcorn needs 1 inch of water per week.
I can tell you from experience (I’m a neglectful plant mother sometimes) that popcorn can grow pretty well with less water than that.
Like all plants, popcorn will do best if it doesn’t have to compete with weeds for resources. We typically weed two or three times in the first month when it’s still small and growing. Once it’s knee-high or taller, the leaves do a good job of shading the soil and preventing weeds the rest of the season. It’s a fairly low-maintenance crop in this way.
I can’t stress this enough: popcorn needs to FULLY DRY on the plant before being picked!
You’ll notice the husks turn from green to yellow to papery dry and brown. As the ears dry, the entire stalk will start to dry as well. If possible, wait until the entire stalk is dead and brown before picking the ears. DO pick them as soon as they are dry though, to prevent pests like rodents and birds from eating them.
Also note that the ears dry from the outside in, so while they might look like they are yellow and dry on the outside, the inner leaves will still be green for a while. How to tell if an ear of corn is actually dry or just appears dry but isn’t, is something you’ll learn with experience.
If you pick the popcorn prematurely, it will not pop as good, and maybe not even pop at all. I know it’s tempting (trust me, I know!) to peek or pick some ears early, but don’t. If the husk has any green on it, do not pick it.
Pick the ears by pulling them with a downward motion off the stalk. Usually the faster and quicker you can pull them, the better!
What about rain?
Don’t pick the popcorn if it is wet from rain; let it dry out first. I look at the forecast and try to time picking when it’s been dry. If the corn is ready or *so close* to ready and there’s a week of rain in the forecast, I’ll pick before the rain.
What about frost?
It’s usually the cold weather of fall that causes me to pick my popcorn. If I am careful (in my short northern growing season) about the varieties I select, they’ll be just dry enough to pick by the time the cold weather forces me to.
Corn that is in the process of drying can tolerate a light frost, so don’t think you have to pick it quickly if an early fall frost is looming.
Hard freeze is different and it depends on how far along the corn is. If the husks are totally yellow and mostly brown and dry and there’s a hard freeze coming, I’ll usually pick it.
If it’s going to get very cold and your corn still has a lot of green in the husk and the kernels are soft and milky, you might lose it as a popcorn crop (you may be able to salvage it as flour corn instead).
Shuck (remove the husks) right away after picking.
When even a little moisture is left in the husks (and there usually is) the corn will start to mold quickly.
If you want the corn to serve as a decoration, peel the husks back one at a time so they stick straight up. If you only intend to use the corn for food, you can shuck the corn quicker by pulling back several husks at a time. Then once the corn is unwrapped, break the husks off from the ear.
Popcorn needs to be dried more after harvest before being stored and before it will pop!
Corn drying happens in two phases: phase 1 drying happens on the plant, and phase 2 drying happens after being picked. Even though we let the corn dry on the plant, it still needs to dry more before it will pop well. It also needs to dry more before storing, otherwise it’s likely to mold.
Set the shucked ears in a single layer somewhere with good airflow. I usually just use an extra table, or a big piece of cardboard on the floor. Corn should be dried in a controlled environment and somewhere where rodents won’t steal it.
How long it takes to finish drying will be different for everyone. Factors like when it was harvested, how dry it was, and the relative humidity can affect how fast it dries. If you are in a very arid climate (I am not), test it sooner than what I recommend below.
The moisture content of popcorn should be between 11 to 15.5% for it to pop well. We have to find the Goldilocks point: If it has too much moisture or too little, it won’t pop well.
Since there isn’t a practical way for home gardeners to measure the moisture content of popcorn, the best way is to test pop it. I typically let my popcorn dry for one month in the house before trying to test pop it. I simply pop a handful of kernels and see how they do. When I get an almost-perfect pop rate, I’ll test a larger quantity from multiple ears to double check. If that pops well too, I know it’s ready!
If it doesn’t pop well, I’ll wait another week and try again. What do you do if it doesn’t pop? If your corn has been drying in the house for 2 months and it still doesn’t pop well, then I’m sorry to say that it probably isn’t going to. It could be the variety, as some corns marketed as popcorn don’t actually pop well (looking at you Glass Gem!). It could be that it came from bad seed stock, it was cross-pollinated, or not dried properly on the plant. This corn still makes a lovely decoration! It can be used for flour, cornmeal, masa… or even treats for your chickens.
How to shell popcorn
Once the corn is popping well, shell it (remove the kernels) and store in an air-tight container immediately!
The goal is to let it dry until it’s perfect for popping, then shell it and store in an airtight container. This will capture it at the perfect moisture level and prevent it from drying too much more.
One of my favorite winter activities, shelling is removing the kernels from the cob. There are several ways to shell corn, some easier than others. For years we used our hands to do this task, but that can get difficult if you have more than a dozen ears. It takes a lot of hand muscle and can tear up your skin if you don’t wear gloves. Then we discovered a corn hand sheller, which was life changing! We grow hundreds of ears every year, and this allowed us to shell it about 10 times faster and with much less pain.
The corn sheller we use is made by Decker and is sold at many different agricultural supply stores. I’ll link to it on Amazon (click here), but I’d recommend shopping around. There is a small and large version, so make sure you know which one you are getting. We have both sizes and use both every year. We use the smaller size more often, but both are necessary if you are a semi-serious popcorn grower.
We sit at the kitchen table with our corn shellers and a couple large baking pans to catch the corn. It’s not a bad way to spend a cold winter’s day! You insert the corn through the center and twist it through. The nubbins in the sheller knock off all the kernels. If you don’t have a corn sheller, use your hands (thumbs, mostly) to push the kernels off the cob. And wear gloves!
How to Store Popcorn
Popcorn is best stored in glass jars to capture and hold its moisture level.
I use large half gallon or quart jars with 2-piece lids (standard canning lids).
Plastic bags are not air-tight and will allow gas exchange through the plastic over time. For this reason, plastic isn’t a great choice, especially if storing an entire year’s worth of popcorn. If you want to store in bags, use mylar instead.
How to pop homegrown popcorn
An air-popper is my preferred method for popping homegrown popcorn!
Now that you’ve learned how to grow popcorn, the next step is learning how to pop it. Homegrown popcorn can be a little more finicky than store-bought, and an air popper (click here) never fails me.
Of course, it can be popped using other methods too. Homegrown popcorn can be popped on the stovetop, but I have had the best luck with an air popper.
If your homegrown popcorn isn’t popping well for you, it’s worth trying an air popper. I also love to drench my popcorn in butter, so I like that I don’t need additional oil to pop it.
How to grow popcorn
Happy growing! Let me know if you have any questions about how to grow popcorn!