Sweetcorn
Introduction
For UK grown varieties, sweetcorn comes in three main colours: yellow sweetcorn; white sweetcorn; and bi-colour. Many other colours of sweetcorn are available, but these can have different culinary uses and may require longer hotter summers (than typical in the UK).
Sweetcorn needs no special care, has a relatively short growing season, and will thrive in the large majority of summers – it requires consistent warmth rather than plentiful sun.
Planting
- Sow in a warm environment like a propagator or on a sunny windowsill
- Planting depth: 2.5 cm
- Planting spacing: 40 cm between plants, 40 cm between rows
Harvesting
- Sweetcorn may need a net (or cage) to prevent birds, mice, rats, and squirrels eating them first
- Pick when the tassels have turned brown (try opening a cob to test for ripeness)
(inside)
(outside)
(fresh)
(stored)
= jar, 
= freeze, 
= store
Varieties
The main decision when growing sweetcorn is choosing the right variety for your growing conditions. There are three main types:
- Normal
- Sugar enhanced (or extra tender sweet)
- Supersweet
Supersweet varieties are said to have twice the sweetness of normal varieties. However, sweetness level is not the only consideration. In general, sweeter varieties are less hardy and need hotter weather to ripen and achieve full sweetness. They are suitable for warmer parts of the UK and for hot summers. On colder allotments, better results may come from growing ‘normal’ sweetness varieties.
The challenge of combining high sweetness levels together with the ability to cope well with British summers is why many varieties of sweetcorn are F1 hybrids. Hybrids are crosses of at least two different varieties, with the intention of preserving the best characteristics of both. Sweetcorn varieties can cross pollinate with each other, which can change the taste of the sweetcorn produced. To avoid this happening, it is recommended to grow only one variety of sweetcorn in your garden or allotment.
For UK grown varieties, sweetcorn comes in three main colours: yellow sweetcorn; white sweetcorn; and bi-colour. Many other colours of sweetcorn are available, but these can have different culinary uses and may require longer hotter summers (than typical in the UK).
The easy way for a gardener to organise their growing and discover gardening ideas.
Growing
Sweetcorn is a frost sensitive plan, and therefore should be planted under protection, or outdoors after the last frosts. The plants grow vertically, so applying a thick mulch, or using biodegradable weed control fabric, can considerably reduce the amount of weeding required around plants. For this reason, some people choose to grow squash and sweetcorn next to each, as the spreading squash provides ground cover around the tall sweetcorn plants, and has the added benefit of helping to retain moisture in the soil.
It is recommended to plant sweetcorn in a grid formation, rather than a row, to maximise the chances of cross pollination by the wind. I leave a spacing of about 40 centimetres between plants in all directions.
On my allotment, sweetcorn is relatively pest free until the very last moment when the sweetcorn is ripe. At this stage, rats, mice, squirrels, and even deer are potential predators. Covering the crop with a net, and ensuring the net has no gaps at ground level, can help prevent an attack. To minimise the risk of animals getting to the corn first, it is better to harvest sweetcorn as soon as the tassels on top of the corn start turning true brown.
Sweetcorn is at its most delicious cooked and eaten as quickly as possible after being picked, as otherwise the natural sugars within the corn turn to starch.