The incredible taste of freshly harvested sweetcorn is something that can never be replicated in the supermarket. Sweetcorn has a reputation for being very difficult to grow but this guide will teach you how to be successful growing your own sweetcorn from seed.
From commercial hybrids, heritage varieties, coloured and mini sweetcorn there are a lot of different options available here. So which is best to grow?
For anyone who is starting out for the first time the mini sweetcorn varieties are the perfect place to begin, they are quick growing, tasty and very easy to get a good crop from. For those who are a little more experienced I would highly recommend heritage varieties, they are developed for our climate, have a wonderful taste and are very reliable.
The commercial hybrids are usually designed to produce a lot of cobs of corn, in many cases these will not all ripen in a garden setting. The taste is very sweet in commercial varieties but I find the heritage varieties to be more flavourful. The main problem with hybrids is that all the sweetcorn will ripen at the exact same time giving a huge sudden glut and as sweetcorn tastes best within a few hours of harvesting storage of this glut can be difficult. I wouldn’t recommend sweetcorn hybrids in a garden.
Sowing Your Sweetcorn Seeds
To get a good crop in the UK you really need to be sowing your seeds indoors before the last frost. In a cool greenhouse or windowsill sowing can begin as early as April and continue until early May.
Sweetcorn can be successful if sown directly outdoors but given the unpredictable weather your crops are really reliant on having a very warm summer.
Sowing indoors will give the chance to establish before the weather is good enough outdoors. Sweetcorn plants really do not like to become pot bound or their roots restricted so growing in a large pot, roottrainers or toilet roll inners is a good option.
Growing Your Plants On
Once established your sweetcorn plants can be planted out after the last frost. It’s essential that you don’t plant outdoors until after the last frost as sweetcorn plants are very vulnerable to cold weather. This will be very dependant on your area and varies yearly but late May or early June are usually the time to be transplanting outdoors.
Before being planted outdoors you will need to harden your sweetcorn plants out to acclimatise them to the outdoor weather, this is done by placing the plants outdoors during the day for a 3-4 days prior to being planted outdoors.
The planting out location is important. The area needs to be sheltered and in full sun. Sweetcorn are a very hungry crop so choosing a plot where there has either been manure or compost recently added will give the growth needed. If a good layer of manure is added then no further feeding will be needed, if the soil isn’t very good a liquid feed will be needed later in the season.
The plants must be planted in blocks rather than rows to allow wind pollination. Plant out at spacings of 14-18 inches apart. You will need at least 8 plants in a block to allow good pollination.
Sweetcorn Top Tips
There are a few things you can do that will significantly increase your success with sweetcorn.
Watering when dry is very important, although sweetcorn can survive drought quite well the growth slows down when the plants are not watered regularly. Due to our short growing season keeping the plants well watered will often give you a crop 2-3 weeks earlier.
When the tassels begin to show tap the plants daily to release the pollen and increase germination.
If you are growing a small number or plants or are in a very windy location it might be best to stake the plants, they can break in strong winds.
Finally, if your soil isn’t good a regular feed of liquid seaweed will increase growth. Mulching with grass, compost or rotted leaves will keep the moisture in the ground as well as feeding the plants.
When To Harvest Sweetcorn
Not being able to see the inside of the sweetcorn cob can make it seem difficult to tell when the sweetcorn are ripe.
Watch out for the tassels of the sweetcorn turning a dark chocolate brown colour, this will be any time from late July to September depending on the season. Once the tassels are brown it’s a good indication that the sweetcorn are ripe. To check the sweetcorn are 100% ripe you can pull back some of the leaves from the cob and squeezing a grain in between your finger, if the liquid that comes out is a creamy yellow colour the corn is ripe.
The cob will pull from the stem easily.
Sweetcorn are best eaten straight from the plant, within an hour they begin to lose the flavour. Pick as close to dinner as possible to guarantee the best flavour possible.
The cobs of corn cannot easily be stored, you can remove the corn from the cobs and freeze it but the taste will never be as good as freshly harvested sweetcorn eaten straight from the plant.