How to grow Corn

This is a guide on how to grow Corn, its sun requirements, when to plant it and harvest. It also covers the different pests that may affect your crop and what you can do about them.

Corn requires well draining soil, enriched with well rotted organic matter. 

Plant Corn in a full sun position, protected from strong winds.

No, Corn plants are not frost tolerant. 

Plant Corn roughly 30cm apart. Since Corn cobs are pollinated by wind, it's important to plant them close together. Plant corn in blocks of at least 3 or 4 rows, rather than a long single row. Planting in blocks allows for a more even dispersal of pollen, producing cobs with even and consistent kernel production. 

Corn is a warm season crop. Standard corn varieties should sown once soil temperatures have warmed above 12°C. Sweetcorn varieties should be sown once soil temperatures have warmed above 18°C.

Corn is usually planted out in spring, depending on your climate. Wait until the danger of frost has passed. 

If transplanting seedlings, plant out in the early morning or evening and/or on an overcast day. Avoid planting at peak sun times or on windy days, this will allow your plants to settle in comfortably and protect them from windburn and sunburn.  

Apply an organic fertiliser to your Corn plants throughout the season.

Corn cobs are generally ready for harvest around 3 weeks after flowering, when the silks at the top of the cobs have turned brown. To be sure, peel back some of the husk and pierce a kernel with your finger nail. It should release a milky liquid. If the liquid runs clear, it needs more time to mature. If no liquid comes out, it means the corn is over-ripe (as the sugars have converted to starch). 

To harvest, grasp the ear firmly, then twist and pull downwards. 

Pests that affect Corn include: Slugs, Aphids, Corn Earworm, Cutworm, Armyworm, Flea Beetle, Thrips, Root Knot Nematode, Mites, Slug, Snail, Leafhopper.

Diseases that affect Corn include: Anthracnose, Fungal Leaf Spot, Bacterial Leaf Spot, Charcoal Rot, Rust, Smut, Downy Mildew, Stalk and Ear Rot, Leaf Blight, Bacterial Leaf Streak Disease, Steward’s Wilt, Mosaic Virus, Corn Lethal Necrosis. 

Shelter Corn on days where strong winds are predicted.