The fresh sweetness of corn in mid summer is a seasonal treat and it doesn’t come any sweeter than when corn is cooked moments after being picked from your very own garden. Sweetcorn is fun for kids to sow and plant thanks to its speedy development - you can almost watch it as it grows. It also benefits many other plants in the garden as a climbing frame and shade provider.
In cooler parts where the summers are shorter grow a fast maturing variety such as ‘Early Gem’. You can also choose from varieties with white, yellow, orange, red or purple kernels. The older Heritage varieties like ‘Country Gentelman’ and ‘Golden Bantam’ are said to be most nutritious.
Companions Beans, squashes, lettuce, zucchini, cucumbers, dahlias, cosmos, sunflowers,
Quantity 6 plants per person.
Heritage varieties are less regular and ears tend to be smaller than hybrids but are said to be more nutritious.Hybrid varieties produce larger, more regular cobs on taller growing plants.
Early Gem heritage variety with golden cobs. Good to grow as an early crop or a main crop in cooler areas with shorter summers.
Golden Bantamn heritage variety with sweet, pale yellow kernels. Strong growing, productive plants.
Chieftan F1 hybrid variety that produces long, full cobs with sweet kernels.
September to December, in warmer areas sow under cover in September and plant out from mid to late October as long as it is warm.
In cooler spots sow under cover and plant out when all risk of frosts has passed and soil has warmed.
Sweetcorn, like squashes and pumpkins cannot handle any frost at all so wait until all risk of frost in your area has passed. In warmer areas it is normally anytime after Labour Day that seedlings are planted out into the garden. You can continue to plant out until the start of January in warmer parts where summer tends to go on for longer. In colder parts of the country you may find you have to wait until December and do all your planting during that month.
Sweetcorn likes a warm place in the sun with shelter from strong prevailing winds. It grows to around 6 foot in height so find a spot where it won’t put any sun-loving neighbours in the shade.
Sweetcorn is a hungry, high performer and likes a well-drained, deep soil with a store of rich nutrients dug through it. Rotted animal manure such as horse manure, chicken poo or sheep pellets are all good for sweetcorn. Dig these in down to at least the depth of a spade’s blade beneath the surface. If your soil is sticky then dig in coarse sand or fine pumice in sufficient quantities so that you can actually see it mixed through the soil to at least a spade’s blade in depth. To further improve drainage for your corn crop you can mound soil up to make a raised – and better draining – planting position.
Sweetcorn is best planted into peat pots to germinate and grow to seedling size before going out into the garden. This gives it a head start in early Spring whilst the soil outdoors is warming up – it also makes it less likely you’ll lose too many from slug and bird activity which often sees rows of sprouting seeds whisked away from the garden when they have been sown outdoors.
Seeds are best popped into a small pot (around a finger length in height) of seed compost and put on a windowsill, in a cold frame or in a greenhouse to grow on and get a head start on the cooler weather or early spring.
Take your seeds and put them in a glass of water to soak overnight before you plant – this will improve germination. Generally, it is a good idea to plant two seeds per pot and then select the stronger of the two when they have developed a pair of leaves (just pinch out the weaker one at soil level).
If you are buying seedlings then go for specimens that are well-rooted and not lying around all over the place.
The trick with sweetcorn is plant in sufficient numbers and to plant in blocks rather than single rows. This is done so that plants are surrounded by one another to ensure adequate pollination – which happens when wind blows pollen from plant to plant. Give plants just over a hand’s length between each other in rows and separate rows by about a forearm’s length.
Just make a hole as deep as your pot and pop the seedling in before back-filling and gently firming the soil around it. Water well and, if you have enough, cover each seedling with a plastic bottle cloche (these are removed when foliage reaches the top).
Sweetcorn can be used as a living trellis for runner beans to scamper up. There is a cool planting combination called ‘The three sisters’ – originating from native American growers – that sees a ring of half a dozen or so sweetcorn plants with a squash or cucumber planted in their midst and a couple of runner bean plants growing up around their outside. The beans clamber up the corn and tie them together whilst fixing nitrogen into the soil. The corn benefits from the extra nitrogen and provides a climbing frame for beans and squash/cucumber. The squash/cucumber climbs on the corn and its broad leaves provide shade at the base of the corn – keeping roots cool and shading out weeds.
Keep well watered if dry. When seedlings come about halfway up your shins earth them up by pushing soil up around the base to about a third their height. This helps them withstand any windy weather. Feed with liquid comfrey or worm juice every few weeks. Mulch to retain moisture – unless growing ‘The three sisters’.
The male flowers will develop and open at the top of the plants with the female flowers growing off the stems in tow or three places on the main stem. When the male flowers form branches and open out you’ll see the pollen falling in clouds when they are given a shake. It’s a good idea to do this just in case insufficient winds dislodge pollen at the right time. Pollen falls onto the female flowers – or ‘silks’ - below and then these develop into corn cobs. This is an important time to maintain good watering and keep growth smooth and uninterrupted by thirst.
Corn cobs can be attacked by caterpillars. If you see any remove by hand. You can use a Tomato leaf spray or Chilli spray as further pest control.
Some years the harvest can start earlier than others – delays can come from colder springs causing an early lack of pollinating bees.
The cobs should start to swell quickly and they are ready to be pulled from the plant by pushing them downwards about a week or so after the silks have turned brown. Sweetcorn is sweetest when freshly harvested because the sugars it contains start to convert to starch once it has been picked.