Spotlight on Sweetcorn

Spotlight on Sweetcorn

A much loved vegetable providing both colour and fibre to a meal. Available as tinned, frozen and fresh or ultra fresh and sweet if you grow your own and can harvest to the plate. Recipes such as sweetcorn fritters, salsa and creamed sweetcorn can be a great way of serving along with barbecued or boiled and buttered

In the UK it can be grown with success and needs a sunny but sheltered site.  There are early varieties that can be sown in more northern parts of Europe and therefore suitable for the UK. These early varieties take a shorter time to mature. Choose from Northern Extra Sweet F1 at 67 days, Solstice F1 at 75 days and Amaize at 67 days(averages). 

Most varieties produce 1-2 cobs per plant and can be interplanted when young with quick growing salad crops. Courgettes also can do well planted alongside as they require similar conditions.

Generally start sowing indoors about 2-3 weeks before the last frost in your area. Sowing can take place from April to June depending on your area and the protection available. Plant in individual pots such as coir pots or toilet roll inners, as this enables transplanting to the final growing area without disturbing the roots too much.

To germinate do so in moist, not waterlogged, general purpose compost at a temperature of 15-20OC (59-68 OF). Once the shoots are 8-10cm (3-4 inches) high start to harden off ready for planting out.

Harden off the young plants by putting them outside during the day for 1-2 weeks before planting in their final position. Transplant to their final site in a block, for example 4x4 or 5x5 at about 45 cm(18 inches) apart. Take care when transplanting as sweetcorn dislikes root disturbance. It can be planted  slightly deep as it will sometimes grow adventitious roots from the stem. If roots are exposed, cover with soil or compost.

In warmer parts of the UK sweetcorn can be sown outdoors. Use large soft drink bottles with the bottoms cut off for a recyclable cloche to warm the ground for sowing or to protect the newly transplanted corn. Sweetcorn sown outdoors or in the greenhouse may be eaten by mice or voles so plant 2-3 per station as insurance but remove weaker shoots and allow only one to grow on at each station. The new shoots may also need protection from birds - particularly pigeons. 

Watering is particularly important when newly transplanted, seed is setting and cobs are filling. Water by  giving a good soaking at least once a week. Water more in particularly hot dry periods especially when the cob is growing. Feeding with a high potassium feed when cobs are setting and mulching around the plants will help retain moisture in the soil and reduce the growth of weeds. Sweetcorn is best weeded by hand as the roots are fairly shallow and susceptible to damage when using a hoe.

Germination of the cob can be erratic leaving gaps on the final cob. To avoid sparse germination, tap the  sweetcorn stems when they have dried off from the overnight dew to allow the pollen from the male flowers at the top of the stem to fertilise the female ones lower down. This can be done every few days and is particularly important in periods of low or no wind movement. Due to sweetcorn being a wind pollinated crop it is best to plant groups of tender or extra sweet varieties away from the standard varieties or the kernels may not be described. This may also be an issue if there are any large fields of maize nearby.

Sweetcorn is susceptible to wind rock and may need support with stakes for individual plants or a stake and string support around the block planting. 

Harvest the cobs when the tassels on the end turn black or brown and when the husk is peeled back the juice from the grains is a milky white. Watery colour means not yet ripe and no juice is over-ripe. Try to harvest immediately before eating as the corn will be at its sweetest. If necessary, store in the refrigerator in its husk for a couple of days.

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