Nothing says summer quite like a fat, juicy corn on the cob dripping with butter.
And when it comes to sweetcorn, homegrown definitely beats shop-bought.
Corn is at its prime (sweetest and juiciest) for only 72 hours, after which most of the sugar has turned to starch. When first picked, the ratio of sugar to starch is typically 80 per cent to 20 per cent. In three days after picking the ratio in non-refrigerated corn changes from 20 per cent to 80 per cent.
Most sweetcorn varieties are ripe for picking 90-100 days after planting, although maturity often differs from year to year depending on the temperatures. In cooler areas, where the season is shorter, it's best to choose early maturing varieties. "Early Marika" from Egmont Seeds is the earliest of the Super Sweet hybrids, maturing at around 80 days.
Before planting, apply a balanced fertiliser to your soil and dig in organic matter. Then sow seeds or plant seedlings in blocks, rather than rows. Corn is wind pollinated so block planting ensures better pollination and ear development. Plant at least three rows for good pollination. That means you'll need at least nine plants. Space rows 60-70 centimetres apart and each plant 30cm apart.
Corn cross-pollinates very easily, so if you want to ensure the corn you planted stays true to type, plant only one variety per season, or plant a couple of varieties of corn that mature at different times. If you plant an early variety and a late variety, the early one should have tasselled out and fertilised the ears by the time the late variety has started to tassel.
The Super Sweet hybrids are particularly popular, because they carry a genetic attribute that gives them up to 40 per cent more sugar than standard varieties. However, if you plant a standard variety next to a Super Sweet hybrid, the super sweet factor will be lost if the corn is pollinated by ordinary sweet corn. But don't just stop at golden corn. There are some really neat varieties to try, like "Hopi Pink" or "Hopi Blue" corn (found at Koanga Institute and sometimes on Trade Me).
"Hopi Blue" has inky-blue kernels and the kernels of "Hopi Pink" are bright pink, with some that are reddy-white. Both are usually ground into flour or cornmeal, but the fresh cobs of "Hopi Blue" can be eaten when young. Traditionally, the cornmeal from "Hopi Blue" is used to make blue corn chips or tortillas. In the United States you can also find blue corn flakes.
When seedlings reach 10cm high, apply a balanced fertiliser. Give them another feed when they get 20cm high.
While corn is reasonably drought tolerant, a lack of water, especially when silks are developing, may affect corn quality or result in delayed harvest and uneven maturity. Water regularly, especially during the critical silking stage.
Corn plants usually produce tillers or suckers near the base of the plant. Some gardeners recommend removing these, as they believe that doing so will encourage plants to produce higher yields and bigger ears. Others say it will actually reduce the yield as the tillers serve as feeders. Removing suckers was a practice that used to be carried out by commercial grows many years ago but is no longer common, as there is no consistent evidence of any benefit from doing so. If you want to carry out your own home studies to determine whether removing suckers is an advantage to plants, remove the tillers of some plants and leave others. To do so, simply snap them off by hand when they're still small.
About three weeks after the silks on sweetcorn form, they'll turn dry and brown. This is the time to pick them. You can double check that they're ready, as the kernels should exude a milky substance when jabbed. Kernels, when maturing, go through several stages: pre-milk, milk, early dough and dough. When harvested too young, the kernels lack flavour. When harvested long after the silks have died, they'll also lack flavour, as the sugars will have turned to starch. The point to pick is when the kernels are entering the milk stage, around 18-22 days after the silks form.
However, if day and night time temperatures are high, maturity may be reached earlier, say 15 days or less, as the four stages through which the kernels pass transpires more quickly. Keep an eye on your plants once silks die to get the optimum harvesting time spot on. If you get it right, you'll be eating delicious sweet corn that's a cut above those from the shop.
The best time of the day to harvest is early morning when the sugar is at its highest level. Place cobs in the fridge straight away.
- © Fairfax NZ News