How to Grow Corn in a Backyard Garden
Corn is one of those crops that really disappointed me as a beginning gardener. I remember trying to grow corn in my garden for the first time. At the time, I knew nothing about pollination or pests, and my corn grew sad little cobs with no kernels. The following year I didn’t try corn again because I had decided it wasn’t worth it.
What’s the Secret to Growing Corn in Small Spaces or Gardens?
To successfully grow corn (especially in my small backyard garden) I had to learn about strategic spacing, hand pollination, and some simple pest prevention. While I’m not a corn growing expert, nor have I grown all types of corn, I finally feel confident enough in my corn growing abilities to share the steps that have worked for me. So, if you are wanting to grow corn in your garden, continue reading below 🙂
Types of corn you can grow in your garden
There are different categories of corn (zea mays), and you might also find that some varieties of corn have the traits of multiple categories. Here is a very general breakdown:
♦Flint corn– has a very hard outer layer, hence the name “flint.” Can sometimes be popped, but not always considered ideal. Not eaten fresh. Often used for ornamental purposes because it comes in a wide array of colors.
♦Sweet corn– starchy, high sugar content, and delicious! Sweet corn is eaten fresh on a hot Summer’s day.
♦Flour corn– A type of corn that is unique because it does feel hard, but it contains enough starch that it can be easily ground into a soft, fine powder or cornmeal.
♦Popping corn– A type of flint corn, but known to be ideal for popping.
♦Dent corn– most widely grown for animal feed, processing, and ethanol. Actually has a dent that forms on the kernal as it dries due to the starches shrinking inside.
I only have experience growing sweet corn and popping corn. This is probably because I focus on garden to table meals, and both of those are types of corn that I use often in the kitchen.
When Can I start Corn Seeds?
This is when things get zone specific! Don’t forget to find your garden zone here because it’s a helpful tool for looking up growing schedules. I find that corn loves heat, and my Southern California (zone 10b) climate allows me to grow corn alllll Summer long, and I even sow a last crop in Fall. Since corn grows so fast from seed, wait until your weather is consistently warm during the day and night temperatures are staying about 50-60 degrees F. I typically start mine in April. You can start later in the warm season too, as corn is very forgiving and tolerates heat well. In fact, corn made my list of 10 heat-loving vegetables & flowers to grow from seed.
Try and succession sow corn throughout Summer. This means starting a new round of corn seeds every few weeks to ensure consistent harvests for the whole season. For more succession sowing tips, read How to Succesion Plant to Maximize Your Harvest. If this is your first time trying to grow corn in your garden, stick with one variety of corn to succession sow (see below for notes on possible issues with cross pollination). This year I am really REALLy trying to stay on top of my succession sowing—my goal is to have sweet corn every week! Hold me to it garden friends!
Tips for starting corn seeds
Due to pests in my garden, I prefer to start my corn seeds in small six-pack containers and then transplant into the garden before they get too big. I don’t even have to bring them indoors because I wait until our weather is nice and warm. If you are ever unsure about whether or not to direct sow seeds or transplant seedlings, read my article that breaks down the truth behind direct sowing and transplanting. It should help you make these decisions in the future.
Corn can also be directly sowed. I simply follow the directions on the seed packet for depth and keep the soil moist. If directly sowing corn, sow the seeds every 3-4 inches, and then thin out your plants later. Ideally you want your corn to be growing 6-8 inches apart.
Ideal conditions for growing corn in the garden
Choose a location that is full sun. Surprisingly, I have corn growing in a raised bed with really rich, loamy soil and more growing in a more clay-dominant garden area. My experience with corn is that it is more forgiving regarding soil type. Corn is a heavy feeding plant, so I top with multiple inches of compost before planting, and will occasionally apply a fish & kelp fertilizer if it looks like they need it. You can read how we amend our garden beds between seasons here.
Also, remember that corn grows tall (always double check the height on your seed packet) so be sure to plant seedlings where your corn will not shade out your other plants in the garden.
Strategic placement. Remember how I mentioned that strategic placement is one thing that can help you grow corn successfully in your garden? I have had the most success growing corn in a square or rectangular plot. It doesn’t have to be a whole field, but arranging your corn plants in a square or rectangular shape can help ensure good pollination. Why? because corn is wind pollinated in nature. Therefore, keeping your corn huddled together (and not spaced out) can help ensure pollination—although see my tips for hand pollinating corn below.
Watering. Corn likes water. It can handle lots of heat, but it does like the soil to stay pretty moist. Mulching your corn can really help with retaining the proper moisture levels. I made the mistake of trying to grow corn thickly in a container once, and it dried out too quickly to properly produce any corn. So, if you are looking to grow corn in containers, keep that in mind!
Once your corn seedlings are outgrowing your container, it’s time to transplant. You might remember in my Tips For Stronger Seedlings article, that you don’t want your corn to become root bound in the pot.
I space my corn closely together because I find this works well in my smaller space. Plant them approximately 6″-8″ apart.
To transplant corn, there’s nothing complicated to do! Simply dig your plant holes and transplant! Your beds should already be amended and ready for your corn, but I do add mycorrhizae to the planting hole. My favorite mycorrhizae is a granular formula that not only has beneficial microbes to develop strong root systems, but it also acts as a gentle fertilizer upon planting. You can view the mycorrhizae I use HERE and use code: randi15 for 15% off at checkout!
If you are curious how I amend my garden beds each season, check out my full breakdown HERE.
Always water thoroughly after transplanting!
Fertilizing corn as it grows
As I always say, if you prep the bed with compost and organic, gentle amendments (like kelp meal or an organic vegetable fertilizer), your corn can grow without extra help throughout the season. If you notice any yellowing on the leaves, have lots of rain, or just feel like your corn could use a boost, I use a liquid fish and kelp emulsion to fertilize during the growing season. Corn plants are heavy feeders!
That’s really all I do for my corn until they start to form ears and tassels! See the diagram below for the anatomy of a corn plant.
How to Hand Pollinate Your Corn
As a small-scale urban gardener, I rely on hand pollination for all my corn. It’s very easy to do and really ensures that I get the most kernel development. Remembr, refer to the diagram above for the anatomy of corn so you can proceed with hand pollination.
If you observe closely, there are certain times of the day that the tassels tend to have the most pollen on them—this is late morning and late afternoon. “Pollen shed” is something that actually occurs for longer than just a day. The tassels will emerge from the plant and can continue to shed pollen for weeks! You want to hand pollinate your corn when there is pollen present or maximum “pollen shed” on the tassels along with silks on the ears. To see if pollen is present, gently shake or tap the tassels and see of any fine yellow powder releases!
In my experience, the tassels emerge before the corn silks, so don’t panic if you start to see the tassels but no corn silks, okay?
With a pair of pruners/snips, clip off a tassel that is currently shedding pollen. Next, proceed to brush the clipped corn tassel over the corn silks. Watch a sample video below↓
Fun fact: every individual corn silk corresponds to a single kernel, so we ideally need pollen to travel down every silk in order to get a corn ear that is fully developed. If every silk does not get pollinated, you’ll see little empty areas on the cob that are shriveled, unpollinated kernels.
My biggest corn pollination tip!
Please PLEASE make sure your tassels have pollen on them. The corn pollen will look like really fine powder. To check if there is pollen, you can gently shake the tassels and see if any fine, yellow dust releases. If you brush the tassels over the silks when they don’t have any pollen, you won’t be doing anything for your corn!
Corn Cross-Pollination Facts & Tips
Corn is very unique. It is one of the few garden vegetables where cross pollination effects this year’s harvest/crop. The topic of cross pollination and seed saving in an urban environment deserves an entire article all its own. A couple years ago, I was lucky enough to attend a seminar on seed saving techniques for urban gardeners and the basics of cross pollination. One day I’ll do a write-up on those fascinating topics, but for the sake of this article, corn is an exception! Cross pollination can ruin your corn crop. For example, if you planted glass gem corn with your sweet corn (and they cross pollinated) you would get a corn that most likely won’t be edible fresh, could be really starchy, or even too hard to eat!
To prevent corn cross pollination, I recommend that beginners simply stick with one variety of corn for that season. If you’d like to grow different varieties, you can plant corn varieties that have different maturity dates, or you can stagger the planting of the corn so they don’t flower at the same time. For example, planting one corn with an 75 day maturity date at the same time as one with 100 days, or planting two different corns with 100 day maturity dates 3 weeks apart. The main idea is to ensure that two different varieties are not flowering at the same time.
Fun fact: corn pollen can travel via wind from one neighbor to another, so if your neighbor is growing corn, it can actually cross pollinate if the wind is right. It is said that in your home garden, planting corn at least 50 feet apart can drastically reduce the risk of cross pollination—but we don’t have that kind of space! Urban gardeners can try my tips above for limiting cross pollination.
Organic Corn Pest Prevention
If you want to grow corn in your garden, be prepared for some pests! Every year I battle corn earworms. Even the name sounds gross. These little pests are the larval stage of moths that lay their eggs on the corn silks and the hatched worms eat your corn! Sometimes they are burrowed so deep into the corn silks that you won’t even know they are there until you go to harvest your luscious corn. One sign of corn earworms are little worm poops in the silks—to me, they look almost like termite damage/sawdust particles. If you see these, chances are you’ve got a corn earworm in your corn silks.
How can I prevent corn earworms from eating my corn safely and organically? I soon learned that a little drop of oil at the tip of the corn ear (where the silks enter the ear) can prevent the earworms from getting into your corn cobs. Simply take a drop of canola, corn, sesame, or olive oil and put it on the silks where they go into the top of the corn ear. In regards to when to apply the oil, one study I read found the oil most effective at preventing corn earworm after pollination. I’ve also heard some gardeners report that if you put the oil on the silks before the pollen has the ability to travel down to the kernels, then you could also be preventing pollination. Honestly, I haven’t had a chance to test out this reasoning, but I have been waiting a few days after hand pollinating an ear to put a drop of oil on the silks.
When to Harvest Corn ~ When To Pick Corn
I’ll be discussing when to harvest sweet corn and popcorn, since those are the only two I have grown and have personal experience with.
Sweet corn. Here are some ways to tell if your sweet corn is ripe for picking:
♦The husk looks plump, as if the corn has filled out.
♦The silks have started to dry. Some look lightly brown, but can vary based on variety. Test a kernel!
♦Use the fingernail test. Carefully peel back the husk and pierce a kernel with your thumbnail. If the juice ends up being milky white, your sweet corn is ready for harvest!
Popcorn. Here are some ways to tell if your popcorn is ready for harvest:
You can also view my IGTV video to see how I harvested my glass gem corn last Summer. It’s a great way to have a visual on when to harvest.
♦The husk has dried. It is no longer green. If it was green, that means that photosynthesis was still happening and it’s not ready.
♦The silks have turned brown and dried.
We have started to use an air popper to pop our popcorn. It is now my preferred method because I get a better rate of popping and don’t need to use oil.
Corn varieties to grow in your garden
♦Glass Gem Corn– opening each ear is like opening a present. You never know what colors you will end up with and they are all beautiful! Glass gem corn is a popping corn that you can view popping in this Instagram post HERE.
♦Ignition – delicious sweet corn variety!
♦Honey & Cream F1
♦Peaches and Cream– a sweet corn variety that performs well here.
♦Amaize– another sweet corn to grow for those summer barbecues. So far, a good variety for zone 10b.
♦Martian Jewel – probably my favorite corn! It can serve multiple purposes (sweet eating too).
When your corn is done
Corn will produce one crop of ears/cobs and then it is done. One plant can typically produce anywhere from 2-4, depending on variety. Once you are done harvesting your corn, you can choose to “chop and drop” the stalks as a form of mulch for the garden. This entails simply chopping down the stalks and spreading them over your soil. The other option is to compost the stalks.
Want to know more about mulch? Read Let’s Talk Mulch for all my favorite tips!
⇓ What are your questions about growing corn? Do you have any favorites to grow? ⇓