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.
Cultivation Of Sweetcorn
Seed is sown usually under glass in the UK in good compost from mid-April onwards. Sow 2 or 3 seeds per 5cm (2in.) pot of multipurpose compost. Rootrainers are also excellent. 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. It 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 45cm (18in.) intervals. At least six is recommended.
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. 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.
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 (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
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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. Click on Britpop for seeds from SimplySeeds.
cv. ‘Earlibird‘ AGM: (Supersweet) Vigorous plants with good sized, uniform cobs. Early cropping.
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. ‘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 cobs are harvested at approximately 10cm in length. Each plant produces up to 6 cobs per plant. Grow away from standard sweetcorn because cross-pollination reduces the size of the normal types if grown too close together. The plant crops after 65 days according to SimplySeeds so also quick growing. Click on ‘Minipop‘ for seeds.
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. ‘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.
cv. ‘Wagtail’ (Supersweet): A main cropping type with an excellent yield. 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. Click on ‘Wagtail‘ to get your seeds from SimplySeeds.