Corn is an amazingly versatile crop but there are some unique challenges to growing it really well. If you’ve struggled with growing corn in the past, here are some handy suggestions that are sure to help!
Ideal Sowing Conditions for Corn
Germination is often poor in cooler conditions, so if warmer weather typically arrives later where you are, start seeds off inside to make sure the plants have enough time to grow and ripen. A temperature of 65-70ºF (or 18-21ºC) gives the best results as this will speed up germination so seeds are less likely to rot. Germinating indoors also reduces the risk of mice or other rodents discovering the seeds and eating them.
Don’t be tempted to sow too early though. Mid to late spring is just fine, because you don’t want to be in a situation where you’ve got plants desperate to be planted out into their final growing positions while frosts are still a very real threat.
Prevent Birds from Uprooting Seedlings
Birds sometimes pull them up recently-transplanted corn to get at what remains of the seeds. To prevent this, and to help them transition to outside conditions, keep them covered with row covers until they’ve rooted out and anchored themselves into their new home, in about two weeks’ time.
Avoid Slow Growth
The most common reasons for slow or lackluster growth include poor light levels (all types of corn need plenty of direct sunshine), not enough moisture, or a lack of nutrients.
Corn is a hungry plant, so it’s important to enrich beds with lots of organic matter such as garden compost then follow this up at planting time with a scattering of a balanced general purpose organic fertilizer.
Don’t plant too close together or you run the risk of disappointingly small cobs. As close as 12 inches (30cm) apart is fine in my wetter climate, but in drier regions you may be better off going to around 16 inches (40cm) apart so plants have more resources to draw on. If it’s dry water really well, aiming at the base of plants to avoid problems with fungal diseases. Consistent moisture will encourage bigger, fatter ears of corn, so it’s hard to over-emphasize the importance of this.
Support Corn in Windy Areas
While a fresh breeze is a good thing for this wind-pollinated crop, strong gusts can occasionally topple plants over. Soft, fleshy growth makes plants more susceptible to falling over, something made more likely when there’s too much nitrogen, so avoid using fertilizers with a very high nitrogen content.
It’s not uncommon to see roots poking through at the surface close to the stems. If this happens, mound soil up over the roots to keep them covered, or just cover the whole area with a mulch of compost, which will help feed the plants too. If you do notice plants getting rocked about in the wind, consider tying them to stakes. Planting in blocks helps plants support each other to some extent, and it has other benefits too…
Prevent Poor Kernel Development
Incomplete or inconsistent kernel development, with the cobs only partly or sporadically filled, is down to poor pollination. The silks protruding from the end of each cob are responsible for carrying the pollen down to the kernels. One strand connects to one kernel, so for complete fill, every strand of the silk must be pollinated.
Getting this right begins at planting time. Because corn is wind-pollinated, it’s essential to plant in a block, rather than a single row. This maximizes the chances of the pollen released from the male tassels at the top of the plants drifting down into contact with the female silks lower down.
If you’re only growing a few plants, try hand-pollinating instead. Wait until the anthers are dangling down from the tassels at the top then cut one of the tassel sections off and brush it back and forth across the silks. Be thorough, so that every strand gets some pollen. You can also tap the stalks on still days to help dislodge the pollen.
Organic Pest Control for Corn
Corn earworms are the caterpillars of a night-flying moth, which lays its eggs on the silks. Once they hatch, the caterpillars make a beeline for the ears. One way to beat them is to drop roughly a quarter of a teaspoon of oil onto the point where the silks enter the ears about a week after the silks first emerge. You could also try planting varieties with tight husks that make it hard for the caterpillars to gain entry, or simply grow an early variety, which stands a good chance of maturing before earworms reach their peak towards the end of summer.
Another pest that can bore into the ears, but more often the stalks, is the appropriately named corn borer. Exposed caterpillars can be controlled with Bt, a spray made with a naturally occurring bacteria, but aim to prevent infections in the first place by keeping your corn patch free of weeds.
Both of these pests overwinter as pupae, so take extra care at the end of the season to remove old plants to your compost heap and, if they have been a problem, dig the area over to expose any that might be lurking below ground, and plant in a different area next year.
Beat Bland-Tasting Sweet Corn
Have you ever had the intensely disappointing experience of tucking into a juicy-looking sweet corn cob only to find it tastes bland? This is the number one reason why paying a little bit more for your seeds really pays dividends – and I don’t like to splash my money about! Hybrid or F1 varieties of sweet corn may cost a bit more but they’re worth every penny, yielding cobs with a superior flavor, especially if you pick one of the supersweet types. Varieties bred for sweetness hold their taste for longer too, but the sooner you cook them after picking, the better.
Another reason behind bland or starchy sweet corn cobs is picking them too late. Pick the ears as soon as the silks have turned brown, no later. If in doubt, check they’re ready by sinking a fingernail into one of the kernels like this. A milky liquid should ooze out. If it doesn’t you’ve left it too late as most of those prized sugars will have turned to starch.
Master these common problems and corn is a wonderfully satisfying crop to grow! Drop me a comment below with your top tips for growing the best corn.