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Family: Poaceae
Binomial name: Zea mays
Life Cycle: annual
Corn varieties can be classified as sweet corn or maize. Sweet corn is usually eaten fresh and has kernels that are yellow or white. Maize is usually dried and used for popping corn, to make maize flour or as a decoration. Maize kernels are often brightly coloured. Both varieties are grown in the same way, though there are differences in when and how they are harvested and stored.
Corn is a warm season crop. Use the table below to identify the best time of year to sow corn seeds in your climate.
JAN | FEB | MAR | APR | MAY | JUN | JUL | AUG | SEP | OCT | NOV | DEC | |
---|---|---|---|---|---|---|---|---|---|---|---|---|
Cool | ||||||||||||
Temperate | ||||||||||||
Sub-Tropical | ||||||||||||
Tropical | ||||||||||||
Arid |
Corn plants are best grown in full sun. Choose a location that will receive at least 6 hours of full sun each day.
Corn plants need a well drained soil enriched with plenty of organic matter. Prepare soil by weeding it thoroughly, digging it over to loosen it and adding aged animal manure or compost. Keep the area free of weeds until planting.
Corn seeds do not require any treatment (eg soaking, stratification) before sowing.
Corn seeds grow best when they are sown directly into the garden.
Sow corn seed in blocks rather than long rows. Corn is wind pollinated and spacing plants in blocks helps to transfer pollen between plants to ensure good even pollination.
Corn is a tender crop that’s sensitive to frost. Do not transplant seedlings or sow seeds outside until all danger of frost has passed.
Corn plants may need watering during the growing season. Water when the soil is dry about 5cm below the surface (test this by scratching away a little soil with your finger). Water deeply in the early morning or late afternoon. Avoid watering the leaves of plants to avoid fungal diseases. Learn more about watering here.
If soil was well prepared no extra fertiliser should be necessary. In poor soil or to give your plants an extra boost, application of a balanced fertiliser or one formulated for fruit and vegetables can be beneficial:
Sweet corn is ready to harvest when the silks at the end of the cobs turn brown and dry. Test for readiness by partially stripping the husk to expose some of the kernels. Pierce one of the kernels: if the juice is milky then the corn is ready to harvest.
Harvest cobs by holding them firmly and pulling them downwards while twisting to separate them from the stem. Eat sweet corn as soon as possible after harvest. Corn can be stored short term with or without its husk in the fridge. For longer term storage, corn can be blanched and then frozen.
Maize is ready to harvest when the silks and husks are dry and have turned brown.
Harvest cobs by holding them firmly and pulling them downwards while twisting to separate them from the stem. Remove the husks and hang or spread the cobs on a wire rack in a bright, well ventilated place for 2-3 weeks. The kernels should be dry not squishy. Store the cobs in a cool, dry place or remove the individual kernels and store them in an airtight container.
Like all plants, corn is susceptible to some pests, diseases and other problems. Below is a list of the most common problems gardeners encounter when growing corn plants: