Sweetcorn is most successful in long hot summers, though many modern cultivars are better suited to our cooler climate.
'Supersweet' cultivars are much sweeter than older varieties and retain their sweetness for longer, but they are less vigorous. It is best not to grow these Supersweet types next to other types as cross pollination can result in poor flavour. Alternatively, ‘Extra Tendersweet’ corn which is almost as sweet and less chewy.
Sow indoors at 18-21°C (65-70°F) from mid-April to early May in modules or deep pots at a depth of 2.5cm (1in). For an extended cropping season, try early, mid season and late cultivars sown at the same time or sow your one early cultivar another two times, 3 weeks apart. In colder regions, early cultivars will do best.
Sow outdoors in late spring. Soil or compost temperatures need to be above 10°C (50°F). Sow 2-3 seeds per station at 45cm (18in) intervals. Thin to leave the strongest seedling.
Grow sweetcorn in a sheltered, sunny position, protected from strong wind, on a fertile garden soil. Add up to two bucketfuls of organic matter, such as rotted manure, and also rake in 100g per sq m (4oz per sq yd) of gerneral purpose fertiliser such as Growmore before planting. Plants are less successful on dry or heavy soil.
As sweetcorn is wind pollinated, plants should be grown in blocks rather than rows, 45cm (18in) apart.
Mulch with organic matter, to conserve moisture and suppress weeds and mound soil over the roots, which appear at the base of the stems. Hoe carefully as they are shallow rooted.
Stake plants individually if they are tall or the location is exposed. Water well in dry weather when plants are flowering. Tap the tops of the plants when the male flowers (tassels) open to help pollination of the female flowers down below; poor pollination results in sparsely filled cobs.
Mice: These rodents will eat the seeds where planted
Remedy: Trapping can be effective for mice in a garden situation, although voles can be harder to control. Break-back traps of the type used against house mice can be effective when set in places where damage is occurring. Pieces of carrot or dessert apple are effective baits for voles, and peanut butter for mice. When using traps or baits out of doors, they must be placed under covers to reduce the risk of other animals interfering with them. Birds are particularly vulnerable to accidental trapping.
More info on Mice
Birds: Birds, especially pigeons, can cause an array of problems including eating seedlings, buds, leaves, fruit and vegetables.
Remedy: Protect the plants from birds by covering them with netting or fleece. Scarecrows and bird-scaring mechanisms work for a while, but the most reliable method of protection is to cover plants with horticultural fleece or mesh.
More info on Birds
Slugs and snails: These feed on the young seedlings and you'll see the tell tale slime trail on the soil around your crop, as well as on the leaves.
Remedy: There are many ways to control slugs and snails, including beer traps, sawdust or eggshell barriers, copper tape and biocontrols.
More info on Slugs and snails
Test for ripeness when the tassels have turned chocolate brown - peel back a little of the husk and peirce a kernel with a fingernail; if a watery liquid squirts out, it is unripe; if it is creamy, the cob is ready; if paste-like it is over-mature. Twist ripe cobs and pull sharply from the stem. They rapidly lose their flavour so harvest when required.
‘Swift’ F1:(Extra tender sweet) One of the best varieties to choose for growing your own sweetcorn in the UK. Plenty of cobs.
‘Golden Giant’ AGM:(Supersweet) A vigorous main season variety with large, good quality cobs.
‘Lark’ AGM:(Extra tender sweet) Early and high yielding with sweet, tender, top quality cobs.
‘Earlibird AGM:(Supersweet) Vigorous plants with good sized, uniform cobs. Early cropping.