Sweetcorn

One of the sweet treats of September and October is sweetcorn or ‘corn on the cob’ which is best eaten after barbecuing or after a gentle boiling. It is also eaten fresh but the cob needs to be fully ripe to really obtain that sweetness. Once the cob is cut, the sugars immediately start being used up within minutes. Believe you me, what ever anyone tells you about sweetcorn from the supermarket shelf, it is only really at its sweetest once its cut from the garden.

The cob is made up of rows of tightly packed golden yellow kernels, growing along a tough central core. Those kernels are packed with natural sugar which is mainly starch. Some varieties are dried and the kernels used to make popcorn. Young cobs known as ‘baby sweetcorn’ are eaten in stir fries but have none of the sugar – it’s their texture that appeals. We have described the structure of the corn or maize kernel elsewhere.

Sweetcorn is also a gluten-free cereal and a source of fibre and vitamin B. Great for slimming with just 100 calories per cob. Don’t add too much butter ! Best eaten as soon as picked or can be eaten raw for the best flavour. Look for Supersweet varieties which have a sweeter taste that is retained longer than ‘normal’ types. Do not grow in close proximity to normal types and so allow cross pollination.

Cultivation Of Sweetcorn

Seed is sown usually under glass (greenhouse or coldframe) in good compost from mid-April onwards. Sow only 2 seeds per 5cm (2in.) pot of multipurpose compost. Rootrainers are also excellent and will take one seed. Sow seeds at a depth of 38mm (1½in.). Water regularly to ensure the shoots do not dry out. Plant out once the risk of frosts have passed which is late May in the South of England or early June in northern Europe. It is possible to directly sow the seed in the south of the United Kingdom from late April onwards when the ground has warmed up a little. Sweetcorn hates cold wet soil or drying parching winds. 

Grow sweetcorn in a sheltered, sunny spot which is protected from strong winds on any fertile soil. Add about two bucket loads of organic matter, such as rotted manure, and also rake in 100g per sq. m (4oz per sq. yd.) of Growmore™ or other proprietary fertilizer before planting out. Plants are less successful on dry or heavy soil so any soil improvement is recommended.

The plants are wind pollinated so they are grown in blocks and not rows. Plant young shoots at between 35cm (14in.) and  45cm (18in.) intervals in late May to early June after hardening off. At least six plants are recommended. Plant in blocks rather than long rows to assist with pollination and increase cob production. To be honest, I plant as far as possible from each other as I can get away with simply because too much foliage is generated rather than cobs. About half a yard or a metre is ideal between plants.

-Feeding

Mulch with organic matter to conserve moisture and suppress weeds around the plants. Mound soil over the roots, which appear at the base of the stems. Hoe carefully as they are shallow rooted. 

Growing Plants On

Stake plants individually if they are tall or the location is exposed. Water well in dry weather; this is vital when the plants are flowering. In fact, water as often as possible as they soak it up. Tap the tops of the plants when the male flowers (tassels) open to help pollination as poor pollination results in sparsely filled cobs. Liquid feed when the cobs begin to swell and harvest between mid-August and mid-September. To be honest, add as much compost, manure and nutrient as possible because your sweetcorn can never have enough of the good stuff. Nitrogen (ammonium sulphate) added throughout the season is a must.

Take care with hoeing. Hand weeding is always preferable given the corn roots grow close to the soil surface. Sideshoots also called the tillers are not removed as they form the part of the base of the plant in some varieties and help maintain stability. Some even generate secondary cobs. 

When sweetcorn is really fresh, the kernels release a milky liquid when cut.

Different varieties can be grown together but you might end up with slightly odd coloured kernels. I find the size and number of cobs depends on how rich and wet the soil is.

Pests & Diseases

Diseases and pests are few.

• A smut (Ustilago maydis) is a fungal disease causing white or grey swellings on affected cobs. These burst to release black spores. Lift and burn affected plants.
• Aphids congregate when tassels are forming.
• Modern cultivars are susceptible to diseases when sown in cold soil as seeds can rot or produce slow, erratic germination. 

Sweetcorn Varieties A – L

Please note this page contains links to our affiliate marketing partner. Please read our affiliate disclosure. If you are looking for popcorn varieties, try Britpop and Robust.

 cv. ‘Earlibird‘ F1 AGM: (Supersweet) Vigorous plants with good sized, uniform cobs. Early maturing producing superb quality, deliciously sweet cobs. It produces a good yield of high quality cobs, approximately 20cm in length, with 16 rows of small grains. Improved tolerance to cold soil helps with germination. Find Earlibird   at Dobies.

cv. Goldcrest. Tall plants , 2.25m (7 &1/2ft.), supersweet, well filled, uniform, even-sized cobs. Goldcrest is the first release from a new Extra Tender x Supersweet programme of hybridization. Two cobs per plant, average cob weight 375g. Available from Kings.

cv. ‘Golden Fleece’: (Multisweet-Supersweet). An early to mid-season variety producing medium sized yellow cobs around 20cm in length, with 16 rows per cob. Excellent for barbecuing.

cv. ‘Golden Giant’ AGM: (Supersweet) A vigorous main season variety with large, good quality cobs.

cv. ‘Golden Lion’  (Extra tender sweet) is a medium early high yielding extra sweet variety. It will produce large cobs up to 21cm long which are evenly filled right too the very tip. Has a very good taste rating and is adaptable to all growing areas.

 cv. ‘Incredible‘. A maincrop sugar enhanced type producing very high quality bright golden coloured cobs around 20cm in length. Each cob contains 16 to 18 golden kernels. Has a super flavour and one of the strongest croppers. 

cv. ‘Lark’ AGM: (Extra tender sweet) Early to mid-season variety and high yielding with sweet, tender, top quality cobs. Crops after cv. Swift. Excellent flavour. The cobs are 21cm length with 18 rows of grains. Good in cold soil and grown up to the lower half of Scotland.

Sweetcorn Varieties M-Z

 cv. ‘Minipop‘ is really the standard for babycorn. Said to have “a very tender pericarp” which makes it ideal for the mini variety. Grown in high density and the cobs are harvested at approximately 10cm in length. Each plant produces up to 6 cobs per plant. Grow this variety away from standard sweetcorn because cross-pollination reduces the size of the normal types if grown too close together. Harvest prior to pollination when the silk tassels begin to show. Excellent when lightly steamed because it is a classic mini vegetable.  Eat raw in salads or have as a pre-dinner dip. The plant crops after 65 days according to SimplySeeds so also quick growing. 

cv. ‘Mirai Music’ F1: tall plants, 2.1m (7ft) – an augmented supersweet type. Bicolour cobs, shorter, very well filled, sweet-tasting cobs. The average weighs 370g. Awaiting appearance in retail.

cv. ‘Mirai Gold’ F1: Shorter plants than ‘Mirai Music’ producing 6ft (1.85m) plants – an augmented supersweet type. Long cobs, straight rows of slightly larger kernels, average cob weight is 385g. Seed found at Mr. Fothergills.

  cv. ‘Northern Extra Sweet‘. (Supersweet).Thought to be the earliest of all the supersweets. It produces long cobs with 14 rows of grain which can be up to 20cm long and are evenly filled. 

 cv. ‘Ovation‘ F1 (Supersweet): An F1 mid-season supersweet variety (sh2). Typically this variety will produce medium sized yellow cobs around 20 to 23cm in length, with 16 rows per cob. Possess good sweet flavour with a very sweet flavour which makes this variety one for the barbecue. 

cv. ‘Sundance‘ F1 (Supersweet): Perhaps the best variety for early maturity in indifferent summers. The cobs are some 18cm (7″) long and close-packed with sugary kernels of creamy-yellow.

cv. ‘Sweetie Pie‘ F1 (Supersweet): An early maturing variety, which can claim to have exceptionally sweet cobs around 22cm (9 in.) long and with an impressive average of 16 rows of corn per cob. Delicious raw or cooked. Buy from Dobies.

cv. ‘Sweet Nugget’: (Extra tender sweet). A very nice medium to long cob size with a strong golden yellow colour. Excellent flavour and better for the cool growing conditions of the UK.

  cv. ‘Swift’ F1: (Extra tender sweet) One of the best varieties to choose for growing your own sweetcorn in the UK. Plenty of cobs. A first early with extra tender corn which was developed for cooler, shorter seasons found in high Northern climates. Produces heavy cobs of good sweet flavour.

cv. ‘Vanilla Sweet‘ F1. A very sweet tasting and early cropping variety. Some say the sweetest of all and the most tender too. Purchase from Dobies.

cv. ‘Wagtail’ (Supersweet): A main cropping type with an excellent yield. Plants are ideally suited for the coldest climates in the UK, especially north of the border in Scotland. Produces very bright golden cobs of 20cm length and 16-18 rows of kernels.

Popcorn Varieties

cv. ‘Britpop‘: (Popping corn). An extremely popular and fast growing variety for the UK. The kernels burst well to produce characteristic fluffy white popcorn. One of the best for this. 

 cv. ‘Robust‘ (Popping corn). A fast maturing popcorn variety producing cobs packed with kernels. These cobs burst into large and fluffy white flakes when popped. Now trialed throughout Europe and is relatively hardy in northern climates.