How to Grow Sweetcorn
Sweetcorn is a form of the maize that once fuelled the Aztec empire. It remains a staple food of the Americas because it is incredibly versatile and nutritious – but unlike most staple foods, its flavour is anything but bland. These yellow, cone-shaped cobs are full of succulent goodness.
Sweetcorn kernels add crunch to stir-fries, pizzas or salads. When cooked with cream and chicken they make a hearty soup called chowder which is a joy to eat on chilly days. However, the greatest pleasure is perhaps a whole cob simply cooked and plonked into a bowl with a creamy knob of butter and salt and pepper dashing.
You may have purchased ‘fresh’ cobs from the supermarket before but were probably disappointed with the outcome, you may even have found them woody, bitter and inedible. If so, you are probably wondering why you would devote a large portion of your precious growing land to cultivating the crop. Well, if you haven’t tried corn on the cob fresh from the garden then you haven’t really tried corn on the cob. Even the best organic stallholders could not bring you anything close to the flavour punch you get from chomping down hard on your own home grown corn. This is because sweetcorn should be eaten less than one hour after picking, and preferably straight away. The moment a cob is picked its flavour is on an auto-destruct timer as it begins to convert all of its natural sugars into starch. In 24 hours it will have lost over half its sugars, so no wonder the cobs you buy from retailers taste foul, most of them have been on the shelf for days, for days! Once you try the real thing you will almost certainly be happy to sacrifice ground for sweetcorn despite each plant only yielding two or three cobs.
Read on if you want to learn how to grow sweetcorn that will sit amongst your most precious bounties at harvest time:
There are literally thousands of varieties of maize in all different shapes, sizes and colours. Some corns are blue, purple, red and even green. In parts of rural Central America each individual village is renowned for its own kind of maize which the locals trade between each other in the larger towns. There are currently ongoing efforts by international organizations to catalogue and preserve the various types in case they go extinct due to incursions by big agribusiness strains.
Here are some exotic kinds of corn for the more adventurous to experiment with:
Sweetcorn with multi-coloured kernels, yellow, red and purple. It has large, sweet cobs but needs to be planted early in Britain.
Minipop produces micro-cobs of the kind you might have had in stir-fries from Chinese restaurants. It grows tall and produces a lot of cobs that can even be eaten raw. It will do fine in our climate.
A pure white sweetcorn with a very creamy taste. It is a late cropper but quite hardy in Britain.
The exotic types are fun but here in the UK we are mostly concerned with growing a few sweetcorn strains that suit our tastes. The following types of corn are standard varieties that are easy to grow in Britain:
Lark is an extra-sweet corn that thrives in the UK due to its ability to withstand cooler temperatures. It also produces its cobs early, though not many of them.
Reliable and well-suited to the British climate. It seldom fails and produces plenty of cobs with a sweet creamy taste.
A UK allotment favourite with a great sounding name. It is a tall variety with big cobs that produces late in the season. It has a succulent taste and can often produce three cobs per plant.
Sweetcorn seeds are the yellow kernels we eat. You can buy packets of kernels that are suitable for planting. You may plant kernels straight into the ground if you wish. But this is not usually the best way to plant corn in the UK because our ground is too hard and cold in springtime. This is particularly true in the north. Instead, it is better to set the plants away in a greenhouse, cold frame or even indoors.
When it comes to planting sweetcorn, earlier is better because the plant takes a long time to grow good, tasty cobs. You need to give the plants a strong start so that they can reach full-fruition during summer before colder months come and stifle the growth. March is the usual time to start sweetcorn off but some keen growers start as early as February indoors. If you miss the boat you can start them as late as May, but be aware that your plants may only have enough summertime to produce stunted cobs.
When setting corn away early you should use a propagator with a Perspex lid to keep your seedlings nice and warm. To keep each seedling separate you could use plastic seed trays with individual cells. But a better way is to save up your old toilet roll tubes and use those; they are fully biodegradable, work well with corn, and mean that you can plant the whole pot.
Get your stack of tubes and cut each in half. Put them into your propagator tray and fill each with compost. Make a 2.5 cm (1”) deep hole in the centre of each pot and drop a kernel in, then press the soil down lightly. Water the whole tray liberally, pop the Perspex lid on and place them in your cold frame, greenhouse, or on your windowsill. Give them a little water daily thereafter – don’t let them dry out, but don’t drown them either.
When the seedlings get to be around 2cm (3/4”) tall you may notice some pots have an extra plant. Pull out the weaker plants and move the tray outside to toughen them up.
Planting (In the Ground)
You can plant your corn pots in the ground from May. Corn needs to be pollenated in order to create cobs and it can’t rely on insects so uses wind instead. You have to help the process by planting your corn in directly adjacent, matching rows.
You will need a large area for a decent amount of corn, so designate a rectangular bed with good drainage that will get plenty of bright sunlight. A bed that has been previously well-manured is good. According to an old gardener’s tale planting corn near runner beans creates tastier corn due to some kind of cross-pollination affinity with plants from native climes. Fun but unconfirmed. However, do not plan to put different strains of sweetcorn near each other, they really don’t like it.
When you have settled on a spot, dig over the ground and remove all weeds. Rake over to make the soil fine.
On the prepared ground, use a bulb planting tool or a trowel to create adjacent rows of cylindrical holes the same depth as your cardboard sweetcorn pots. The holes should be 35cm (14”) apart with 60cm (24”) between rows to form a big rectangular grid. Now place one of your sweetcorn tubes into each hole and pack them in with soil. Water the whole area well and leave the rest to nature.
The plants should settle outside and gain strength and size within a few weeks. Keep the ground around them weed free at all times – sweetcorn craves loads of sunlight so don’t let anything get in the way.
In the hottest months keep your corn well-watered at the base so as not to burn the leaves. You may also wish to scatter some organic fertilizer granules.
In windy areas it is fine to tie your corn to a cane if need be. Mounding up earth around the base of each stem will also help with support.
Your corn will be almost ready when you start to see long white silky threads trailing from the cobs. Keep an eye on these threads because when they turn brown it’s time to pick. You can test a cob by carefully opening it and squeezing a kernel. If the juice is watery then allow the cob a few more days, if it is milky you are good to go. Twist cobs off with your hand and run home to cook them before they go bad!
Now you know all about growing sweetcorn, what are you waiting for, go ahead and start stacking cobs!