Corn is a heat-loving veg with varieties for eating fresh or drying to make popcorn or maize. Botanically, sweet corn is actually an impressively tall grass, and the kernels are mature seeds. Plant sweet corn in blocks to achieve even pollination.
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.
When to Sow Corn Seeds
Corn is a warm season crop. Use the table below to identify the best time of year to sow corn seeds in your climate.
Low humidity with most rainfall in winter; hot dry summers and cold winters. Some regions will experience frosts and snow. Includes coastal areas of south-eastern Australia and alpine areas of Victoria, NSW and Tasmania.
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.
How to Sow Corn Seeds
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 seeds directly in the garden 15-25mm deep and 20-30cm apart, with rows 50-90cm apart.
Keep soil moist but never wet or dry.
Seeds should germinate in around 5-14 days at a soil temperature of 16-35°C.
Young seedlings will need protection from pests, pets and weather until they are established.
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.
How to Grow Corn
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:
Apply slow release fertiliser at the recommended rate when transplanting or when seedlings are 5-10cm tall.
Apply liquid fertiliser at the recommended rate and frequency while plants are fruiting or flowering.
How to Harvest Corn
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.
Common Problems when Growing Corn
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:
Aphids are small (2-4mm long) sap-sucking insects that congregate on the new shoots or the undersides of leaves. They can cause leaves to wilt or become discoloured, and also excrete honeydew which can attract ants and other insect pests. To manage aphids, remove them by spraying with a garden hose, apply a soap or alcohol spray, or encourage predatory insects to your garden. Read more about aphids here.
Empty or missing kernels on cobs is caused by poor pollination. Each kernel on a cob of corn is fertilised individually by pollen carried by wind from the tassels (male flowers) to the silks (female flowers) at the end of the cobs. Growing only a few plants, insects eating the silks and water stress can all impede pollination. Once silks emerge, catch pollen in a small bowl by gently shaking the tassels, then dip the silks into the bowl to transfer the pollen. Plant corn in blocks rather than rows, manage insect infestations and water regularly when silks emerge.
Slugs and snails are molluscs that feed on tender leaves and shoots, mostly at night, leaving slimy trails behind them. Control them by removing their hiding places, keeping free range poultry, collecting them by torchlight or by placing traps. Read more about slugs and snails here.
Armyworms, cutworms and other caterpillars can all eat the inside of fruit, making it inedible. Young caterpillars burrow into soft fruit, leaving just a small telltale hole on the fruit’s skin. Monitor fruit and remove any caterpillars you see. If necessary use insect exclusion netting or fruit bags to physically protect the fruit, or spray with Dipel.
Possums, birds and other animals can ruin a large percentage of your harvest overnight. Physically exclude pests by using netting or cages, or try spraying plants with a pungent homemade spray made from garlic, fish oil or mustard.
The term ‘The Seed Collection Pty Ltd’ or ‘us’ or ‘we’ refers to the owner of the website whose registered office is . Our ABN is 61614299697. The term ‘you’ refers to the user or viewer of our website.
The content of the pages of this website is for your general information and use only. It is subject to change without notice.
Neither we nor any third parties provide any warranty or guarantee as to the accuracy, timeliness, performance, completeness or suitability of the information and materials found or offered on this website for any particular purpose. You acknowledge that such information and materials may contain inaccuracies or errors and we expressly exclude liability for any such inaccuracies or errors to the fullest extent permitted by law.
Your use of any information or materials on this website is entirely at your own risk, for which we shall not be liable. It shall be your own responsibility to ensure that any products, services or information available through this website meet your specific requirements.
This website contains material which is owned by or licensed to us. This material includes, but is not limited to, the design, layout, look, appearance and graphics. Reproduction is prohibited other than in accordance with the copyright notice, which forms part of these terms and conditions.
All trademarks reproduced in this website, which are not the property of, or licensed to the operator, are acknowledged on the website.
Unauthorised use of this website may give rise to a claim for damages and/or be a criminal offence.
From time to time, this website may also include links to other websites. These links are provided for your convenience to provide further information. They do not signify that we endorse the website(s). We have no responsibility for the content of the linked website(s).
Your use of this website and any dispute arising out of such use of the website is subject to the laws of Australia.
We are committed to ensuring that your privacy is protected. Should we ask you to provide certain information by which you can be identified when using this website, then you can be assured that it will only be used in accordance with this privacy statement.
We may change this policy from time to time by updating this page. You should check this page from time to time to ensure that you are happy with any changes.
What we collect
We may collect the following information:
name and job title
contact information including email address
demographic information such as postcode, preferences and interests
other information relevant to customer surveys and/or offers
What we do with the information we gather
We require this information to understand your needs and provide you with a better service, and in particular for the following reasons:
Internal record keeping.
We may use the information to improve our products and services.
We may periodically send promotional emails about new products, special offers or other information which we think you may find interesting using the email address which you have provided. You will have the option to opt-out of all non-essential email.
Any personal information which you supply will not be divulged to a third party unless that third party is integral to the purpose for which you gave us your information or where required by law.
We are committed to ensuring that your information is secure. In order to prevent unauthorised access or disclosure, we have put in place suitable physical, electronic and managerial procedures to safeguard and secure the information we collect online.
A cookie is a small file which asks permission to be placed on your computer's hard drive. Once you agree, the file is added and the cookie helps analyse web traffic or lets you know when you visit a particular site. Cookies allow web applications to respond to you as an individual. The web application can tailor its operations to your needs, likes and dislikes by gathering and remembering information about your preferences.
We use traffic log cookies to identify which pages are being used. This helps us analyse data about webpage traffic and improve our website in order to tailor it to customer needs. We only use this information for statistical analysis purposes and then the data is removed from the system.
Overall, cookies help us provide you with a better website by enabling us to monitor which pages you find useful and which you do not. A cookie in no way gives us access to your computer or any information about you, other than the data you choose to share with us.
You can choose to accept or decline cookies. Most web browsers automatically accept cookies, but you can usually modify your browser setting to decline cookies if you prefer. This may prevent you from taking full advantage of the website.
Links to other websites
Our website may contain links to other websites of interest. However, once you have used these links to leave our site, you should note that we do not have any control over that other website. Therefore, we cannot be responsible for the protection and privacy of any information which you provide whilst visiting such sites and such sites are not governed by this privacy statement. You should exercise caution and look at the privacy statement applicable to the website in question.
Controlling your personal information
You may choose to restrict the collection or use of your personal information in the following ways:
If you have previously agreed to us using your personal information for direct marketing purposes, you may change your mind at any time by writing to or emailing us.
If you believe that any information we are holding on you is incorrect or incomplete, please write to or email us as soon as possible and we will promptly correct any information found to be incorrect.