Introduction

Sweetcorn is a type of maize and both are in the Poaceae grass family. They are vigorous plants and easy to grow, but it’s less easy to achieve a harvest before others do – see ‘Pests’ below.

An example is badgers, who often strip sweetcorn plants at Homeacres just before I want to pick the cobs. They are powerful animals and difficult to keep out of a garden.

My remedy has been mainly not to grow sweetcorn, and this is one reason why there are fewer photos here than I would have liked.

Plants of sweetcorn grow tassels of flowers at the top, which drop pollen on the hairs of each cob. Every hair is attached to a potential kernel or grain of corn. If pollen drops or floats by, and is received by the green hairs, then kernels can swell to a full and juicy size. If not, cobs are empty or have gaps. The cobs have an outer sheath of green leaves, wrapped tightly around.

• In American English, cobs are ears and hairs are silks. The outer sheath of leaves is a husk.

In the 1990s I lived in Southwest France, where maize is grown a lot for harvest as dry grain, some of which goes to feed poultry. Seeing how easy the climate is for growing sweetcorn, I grew and harvested some to sell on my market stall in the local village.

• I thought that they would love it, as a vegetable they had not thought of eating.
• The result was delicious sweetcorn and zero sales, with the common comment ‘this is duck food’!

Never mind, we know it is delicious! There are many varieties that have been bred to grow sweetcorn, rather than dry maize. They are an absolute treat when you harvest at the best time, before the pests do!

Harvest period

• Days from seed to first harvest: 80 for early varieties grown in warmth, commonly 95

• Best climate has warm summers, with afternoons of 21 °C/70 °F and higher, not too dry.

Why grow them

Homegrown sweetcorn, freshly picked, has significant dimensions of flavour and sweetness compared to cobs you can buy. One reason for this is that sugars in newly harvested cobs start to convert to starch after being picked. Therefore, when you buy sweetcorn it’s usually less sweet than homegrown. It probably has fewer other flavours too, because the field soil is unlikely to be as healthy and fertile as your soil.

The hybrid supersweet varieties do retain sweetness for longer after picking, compared to older varieties. As do the varieties I recommend here, bred in Germany where they have concentrated on maintaining sweetness after harvest.

Pattern of growth

Plants grow rapidly in warmth, up to 1.5–1.8 m/5–6 ft high, according to the variety grown.

Sweetcorn cobs contain hundreds of immature seeds, the kernels we value, which grow to dry seed if not picked when fresh and sweet. They are an annual plant, which in nature will regrow the following year from any seeds that survive the winter. In our case, we need to either save our own seeds (difficult, see below) or buy new seeds every spring.

Plants are killed by frost, so the growing season is limited either end by the last and first frost dates. Sweetcorn’s growth and harvest timings are governed by season length and the warmth of days in summer.

• If your summers are normally cool, it’s worth raising transplants under cover to have them ready straight after the last frost date.
• In cool regions you can grow sweetcorn in a polytunnel.

Suitable for containers/shade?

These warmth-loving plants grow better in full sun. They are also large, with extensive root runs, and so I do not recommend them for containers.

However, if this is your only option, it is possible to grow two plants per 15 litre/4 gallon container. They will need feeding plus a lot of watering, and also some staking and securing to stop the container from blowing over once the corn plants are quite tall.

Varieties

Two German-bred varieties called Mezdi and Tramunt give amazing results here. The former matures about two weeks earlier, while the latter uses those extra two weeks to grow fatter and sweeter. They are open-pollinated, yet retain sweetness for up to two days after harvest. Neither of them matures super early.

I find that the earliest varieties do not grow the largest or sweetest cobs. However in colder climates they are worth growing, in order to ensure growing time for kernels to sweeten. Best consult your local seed sellers.

Earlibird is more mid-season than early and grows an excellent harvest.

Northern Extra Sweet is a little later and with no extra sweetness that I noticed, but the harvest is bountiful.

In F1 hybrids I recommend Sweet Nugget, for good size cobs which retain sweetness.

Minipop F1 is a babycorn variety that can grow up to five small cobs per plant.

You can grow popcorn in the garden, but I have no experience of this because it needs a summer hot enough to mature cobs with dry grains. Rodents can be a problem because they like unpopped corn.

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