Homegrown sweetcorn slathered in melted butter has always been a favourite of mine – and I suspect yours too, which is what makes poorly filled cobs like the one above so frustrating!
Let’s do something about it! Want to know how to get the very best full cobs of corn from your garden? Here are my essential steps to a perfect, oh-so delicious crop!
Corn Pollination Basics
If your corn doesn’t get properly pollinated, it can’t produce those creamy kernels – it’s that simple! To find solutions to this, let’s start by looking at how corn is pollinated. Corn is actually a type of grass, and like other grasses, the flowers are wind pollinated. Corn produces separate male and female flowers, with the male flowers, called tassels, sitting right at the top of the plant. Up here they can catch the wind, enabling the pollen to be carried off in the breeze.
The female flowers are located further down the plant and are what will eventually form your ears of corn. The female flowers have protruding silks, whose job is to intercept some of the pollen drifting down from the tassels above. Remarkably, each silk strand is responsible for producing one kernel of corn. So, every single strand must be pollinated if we are to get a fully filled cob.
Pollination is simply a numbers game. Each tassel produces two to five million pollen grains, which equates to around a thousand pollen grains for every silk – and it only takes one of them to pollinate! And yet, despite this, perfect pollination is far from a given.
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Planting sweetcorn in a block rather than long rows maximizes pollination success
Plant Sweetcorn in a Block Pattern
Farmers achieve well-filled cobs because their fields are on a far bigger scale than any garden. Rows and rows of corn, swaying and jostling together in the breeze, ensures there’s rarely an issue with pollen distribution.
Gardeners don’t have it so easy, but we can begin helping ourselves by at least planting in a block formation, rather than in long rows. While corn can pollinate itself, around 97 percent of the silks on a plant are pollinated by neighboring plants, so if we were to plant in a row the opportunity for the silks to intercept pollen of any kind would be dramatically reduced. Plant your corn around 14-16 inches (35-40cm) apart in both directions.
Most gardeners won’t grow more than a modest block of, say, 10 to 50 plants, so achieving a meaningful block is always going to be a challenge, so let’s look at the next step.
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Shake corn stalks if the weather is still to release the pollen
Improve Wind Pollination
The tassels are at their peak when the anthers dangling down along their length are a bright, creamy yellow. Drifts of pollen are released every time the anthers are disturbed, and we can use this to our advantage.
If conditions are calm when the pollen is ready, help things along by gently shaking the stalks of the plants. This mimics the wind and will release clouds of the pollen to float down to the silks below. The silks tend to mature a few days later than the tassels, and even silks on the same cob emerge in succession, starting with those lower down and finishing with those at the tip of the cob. So, shake your plants every few days for as long as the tassels are viable to increase the chances of every silk being pollinated.
Pollen is at its best around mid-morning, once any dew has evaporated but before it gets too warm. Pollen becomes less viable above 90ºF (32ºC), so if you regularly get these kinds of temperatures, the relative cool of the morning offers the best chances of finding pollen in its prime. If you aren’t around in the mornings, then shake your corn in the evening once things have cooled off a bit.
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Stroke the corn silks with a ripe tassel to transfer pollen directly to where it's needed
Hand Pollinating Sweetcorn
To absolutely guarantee kernel-crammed cobs you can also hand pollinate. Carefully detach a tassel from the top of the plant – scissors are best to prevent the pollen from being jolted free too soon. Then simply dust the tassel back and forth over the silks, taking care to cover every single strand. Repeat this process every few days with fresh, pollen-filled tassels, again taking the time to reach all the silks.
The silks themselves have a relatively high water content, which means the best way to ensure they successfully emerge and then remain as receptive as possible is to keep your plants properly watered. If the weather is dry, thoroughly soak the soil at least once a week.
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Improving pollination is a sure way to corn cob success!
The silks will dry out once their job is done and then all that’s left to do is wait for those kernels to swell. Eventually the silks will turn completely brown and brittle. Then, to tell if sweet corn is ready to pick, gently peel back enough of the husk to expose some of the kernels beneath. Sink a fingernail into one of the kernels and if the liquid that comes out is nice and creamy, you’re good to go. Bliss!
