Sweet corn is a delicious and popular vegetable, that comes with a whole host of health benefits. Find out the answers to Google’s most-asked question about this plant, so you can grow your own at home.
Are Sweetcorn and Maize the same thing?
Sweetcorn is actually a variety of Maize, which is a term more often used in agriculture.
By weight, Maize (or Sweetcorn) is the most grown cereal grain globally. In just 2021, 1.2 billion tonnes of Maize were grown and used in food, drink, fuel, and fishing!
The variety that is most used as the corn that we enjoy in our meals is Zea mays var. Saccharate. This variety is much sweeter than other varieties of maize, having a higher sugar content. This is where it gets its common name: ‘Sweet’ corn.
What’s the difference between mini Sweetcorn and regular-sized?
Baby corn is basically the immature version of Sweetcorn, which are harvested when silks are 2-3 inches long. Because the baby corn is immature, the hard cob in the middle isn’t fully developed so is also edible!
Is Sweetcorn healthy to eat?
Sweetcorn is packed full of vitamins, minerals, and fibre. This makes it particularly good for eye health, thanks to its content of carotenoids lutein and zeazanthin. There are even studies suggesting that eating corn can lower your chances of developing macular degeneration.
Its high amounts of fibre can help you to feel fuller for longer, plus its magnesium and potassium content helps reduce tiredness. This makes it a great vegetable to add to a post-workout meal, or maybe even baby Sweetcorn as a snack.
Are Sweetcorn annuals, biennials, or perennials?
Sweetcorn is an annual crop that you will need to sow again the following year.
Where should you grow them?
Sweetcorn can be grown wherever it is convenient for you. So good news, you don’t need to include them in your crop rotation.
Though, I would avoid growing them in the exact same spot year in and year out, for too long as eventually, they will lose out on the nutrients they need to thrive.
Which garden style are best for Sweetcorn?
Ideally, you’d grow them in your allotment or grow-your-own area. However, if you don’t have an allotment or much space, then Sweetcorn makes a great addition to a potager-style garden.
A potager garden uses the principles of garden design to enhance a veg plot. So, alongside your carrots, peas, potatoes, and Sweetcorn, you would grow ornamental plants like roses, chamomile, borage, and poppies.
I’m pleased to say that Sweetcorn is a straightforward veg to grow. But there are a couple of things to consider before you start.
Sweetcorn is tall, so it’s not a plant that works as well when grown in a container.
To protect seedlings, grow Sweetcorn amongst salad or spinach. Choose the variety of seeds you want to grow based on your palate. Read the seed packet carefully before buying and know where you are growing the plant for greater success.
Then, prepare the ground. Ideally, Sweetcorn is grown in a sheltered spot that is warm and has lots of sun. Work the soil to improve drainage and well-rotted manure.
Sweetcorn is a type of grass and is pollinated by wind. To increase the chances of pollination, good practice is to grow Sweetcorn in blocks rather than rows.
As Sweetcorn is a tender plant, you ideally need to start this crop off indoors.
You do this as you can maintain a more consistent temperature and can more easily protect young plants from pests.
On a warm windowsill, sow the seeds approximately 2.5cm or 1 inch deep in toilet roll tubes, pots, or module trays.
Sow the seeds individually, to minimize root disturbance.
Once the seedlings have reached a height of 8cm or 3 inches, they are okay to grow outside.
However, if space is at a premium, then you can sow seeds outdoors.
You just need to wait until late spring to this. And protect your seedlings from pests.
Sow your seeds 2cm deep in a block or grid formation, leaving 34cm – 45cm (13-18 inch) gaps between.
With outdoor sowing, sow two or three seeds, this will help with any failed seedlings, and you pinch out any extras.
How long do they take to germinate from seed?
Germination for your indoor sown seeds is around 2 weeks.
For seeds sown outdoors, germination may take longer as you cannot control the temperature as easily. Keep the soil warm with cloches or horticulture fleece to help with this.
When should you plant out your indoor-grown Sweetcorn seedlings?
The best time, is once the risk of frost has passed completely. In the UK, your best bet is to aim for late May to completely avoid frost risk, but every season is different.
How often should I water the seedlings?
Water regularly until the seedlings are well established. Sweetcorn once established, only needs to be watered in hot weather, whilst flowering, and as the cobs begin to swell.
How do I know when my Sweetcorn is ready to harvest?
Sweetcorn is often ready to pick about 20 days after the silk first makes an appearance on the plant.
To check that the corn is ready, you can make sure it is in the ‘milk stage’. To do this, puncture a kernel and look for the milky liquid inside, indicating that the corn is ready to harvest.
If the liquid is clear, it is not ready to harvest yet. If there is no liquid, then the plant is overripe.
How big do they grow?
Typically, they grow up to 2 metres tall, which is about 6.5 feet. This depends on the variety you grow, some known to reach 7 feet or more.
Are Sweetcorn frost hardy?
Sweetcorn is generally quite tender, so it doesn’t tolerate freezing temperatures well. By sowing your seeds indoors in spring, you can avoid the last frosts and plant them out once it warms up.
When does Sweetcorn flower?
Sweetcorn flowers are referred to as tassels. These are also the male part of the plant. As wind moves through the tassels, this pollinates the female flowers that are referred to as silks.
Sweetcorn Tassel
Sweetcorn Silk
Do they need a lot of water?
Not particularly, no. They require watering regularly whilst the plant is still establishing, but once it is growing well it only needs watering when it is hot and dry, and once the cobs are starting to swell.
Does Sweetcorn need staking?
Because Sweetcorn grows quite tall, they can be damaged by being rocked by the wind. If this starts to happen, you can support individual plants with bamboo canes.
To support a whole row of plants, you can insert several bamboo canes around the outside of your block of Sweetcorn plants, tie some string to each end, and link your Sweetcorn plants together with it.
Why does my Sweetcorn have side shoots?
These are called ‘tillers’ or ‘suckers’, I have them on my Sweetcorn plants in the garden. They often happen when the plant grows in favourable conditions, and aren’t anything to worry about, they won’t harm the plant.
You can remove these side shoots if you would like, but there is a good chance they could produce cobs if given enough time to mature.
What are the common problems with Sweetcorn, and how do I fix them?
Wildlife are particularly fond of Sweetcorn when they are seedlings. Slugs and snails are partial to a snack on your young Sweetcorn plants.
As the corn matures, birds, mice, and squirrels make a good meal out of them.
There are a few natural deterrents for slugs and snails that you can try. Dried-up, ground eggshells can create a sharp border around your individual plants that they may find difficult to travel over.
Additionally, you can create a garlic drench with two crushed garlic cloves and two pints of water. Boil the mixture for thirty minutes, then strain the liquid off. An old plastic milk bottle makes a good container to drench the area you are protecting.
Also, if your standard corn cross-pollinates with a ‘supersweet’ variety, or vice versa, the resulting kernels can have poor flavour. To avoid this, grow your ‘supersweet’ and standard varieties separately.
Is Sweetcorn poisonous to pets?
Sweetcorn is safe for your pets to eat. It is quite a healthy addition to a dog’s diet, in moderation. As it contains quite a large amount of sugar and carbohydrates, make sure not to give too much to your furry friends.
You may find that corn is present in a lot of cat and dog foods that you already give them.
Sweetcorn are delicious and towering vegetables that are well worth growing in your garden. If you have any questions about this or any other plant you want me to do a video on, please subscribe to my YouTube channel and leave a comment below one of my Google Questions videos.
David Domoney is a Chartered Horticulturalist, Broadcaster, and Author. David has worked with a number of the UK’s leading garden retailers as a plant buyer and strategic consultant. With more than 30 years experience, in horticulture, David is as passionate about plants now as he was when he bought his first plant at a village fete.
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