Fruit vegetables
Sweetcorn
Zea mays convar. saccharata
Timings for your region
Suggested: Moderate · Explained in the glossary
Start indoorsmid April – early May
Sow outdoorsearly May – early June
Plantingmid May – early June
Harvestearly August – late September
Practical tip
Always plant in a block, never a single long row — sweetcorn is wind-pollinated and a lone row barely sets kernels.
Origin & history
Maize was bred from the wild grass teosinte in Mexico some 9,000 years ago and reached Europe on Spanish ships after 1500. In Germany it was purely a fodder and grain crop for centuries; sweetcorn only caught on in gardens in recent decades, once early-ripening varieties appeared. A neat piece of botany: every single silk thread on the cob belongs to exactly one kernel — a full cob carries several hundred of them.
Varieties
Sweetcorn comes as normally sweet (su), sugar-enhanced (se) and supersweet (sh2) types; supersweet varieties hold their sugar longest after picking but germinate markedly worse in cold soil. Keeping them apart matters: if supersweet corn stands next to ordinary sweetcorn, popcorn or fodder maize, the drifting pollen turns the kernels starchy — so grow only one type per garden. For German summers pick early-ripening varieties; almost everything on sale is an F1 hybrid.
Care
Sweetcorn is a hungry crop and needs warm soil well supplied with compost, plus steady moisture from the time the tassel emerges — drought during flowering costs kernels directly. Once the plants are knee-high, earth up the base of the stems: maize sends out strong prop roots above that point and stands up far better in summer storms. Raise plants individually in pots and never prick them out — maize resents root disturbance and grows on poorly afterwards.
What can go wrong
The commonest mistake is sowing too early: below roughly 10 °C soil temperature maize does not germinate, it rots, and the row comes up patchy. Crows and pigeons pull the seedlings straight back out with the seed attached — netting or fleece over the row until the four-leaf stage settles that. The corn borer overwinters as a larva inside the stalks, so chopping and composting the stubble after harvest instead of leaving it standing removes its winter quarters.
Harvest, storage & kitchen
A cob is ready when the silks are brown and dry and a kernel pressed with a fingernail releases milky juice — clear juice means too early, doughy means too late. The sugar turns to starch quickly once the cob is snapped off, so sweetcorn should go into the pot the same day or straight into the cold. Blanch any surplus briefly, then strip the kernels off the cob and freeze them.
All timings are guide values for the given climate, not a guarantee. Weather, aspect and variety all have a say.