How to Grow Sweet Corn

Sweet corn belongs to a family of nutritious vegetable seeds that taste absolutely incredible when sown, grown, and harvested straight from the garden. Ideal for growing in a warm and bright garden, this spring vegetable grows throughout spring and into summer, when it is ready to be picked, prepared, and savoured on a sunny day.

From bicoloured corn to iconic yellow cobs, there is a wide variety of sweet corn seeds that gardeners can grow in their own garden, and in this Mr Fothergill’s guide, we will cover everything you need to know for sowing, caring for, and harvesting your own sweet corn.

Sweet Corn Classification

Family

Poaceae

Genus

Zea

Sweet Corn Seed Varieties

Sweet corn comes in different varieties that each pack a colourful and flavourful punch. At Mr Fothergill's, we offer a wide selection of sweet corn seeds that grow well in Australia, including:

• 
  Terrific F1
  
• 
  Early Extra Sweet F1
  
• 
  Snow Gold Bicolour
  
• 
  Kelvedon Glory
  
• 
  Super Sweet F1
  
• 
  Sun & Snow F1
  

The first step in learning how to grow sweet corn is identifying the best time of year to sow the seeds. Corn absolutely loves the warmth, so it’s integral that you begin sowing once the frost has passed around October or November, as it cannot thrive in a frosty garden.

Sweet corn can be direct-sown outdoors once the risk of frost has passed and the soil is nice and warm. In cooler climates, you can give your seeds a headstart to the season by sowing them indoors or inside a greenhouse. Ideally, if starting indoors you should sow your sweet corn about three to four weeks before your last frost date, giving you a head start before the soil has warmed up enough to host the seedlings. For more information on indoor sowing, take a look at our guide on how to sow seeds indoors.

Once you have identified the ideal period for planting your sweet corn seeds, you must understand the correct way to sow them. Start with a general-purpose or seed-starting potting mix, such as our Coco Fibre Mix, or a series of smaller pots, sowing two seeds to each pot. Aim for a depth of approximately 1 cm into 11 cm pots like our Coco Fibre Pots, which are ideal for growing corn indoors as they eliminate transplant shock by being planted into the garden themselves during the transplanting process.

Once your sweet corn plants have grown to approximately 15 cm tall, they can be planted outside. To prepare them for the new conditions, allow your plants to harden off by leaving them outside for increasingly longer spells for about a week before transplanting. 

Next, transition your sweet corn to the garden. By using coco fibre pots, you can eliminate transplant shock by planting the pot into the soil, resulting in no root disturbance. Prepare a hole for each plant at a distance of around 45 cm.

Plant your sweet corn in a block in your garden, rather than in a long row. This is because it is wind-pollinated, and planting in a row can lead to poorer pollination and, as a result, the underdevelopment of kernels atop the grown cob.

Successfully caring for sweet corn comes down to sticking to the basic principles of ensuring your seeds are sufficiently watered and monitored on a regular basis.

Ensure that your sweet corn seeds are regularly watered while they are still in their pots, ensuring the soil is consistently moist. Once in the garden, keep an eye out for weeds that may sprout within your sweet corn’s patch and remove them by hand.

In terms of posture, sweet corn is a strong vegetable and shouldn’t require any additional support to grow properly. Remember to consistently water your sweet corn, especially during the warmer summer months when the cobs are beginning to form and drought is more likely. 

Sweet corn is a great companion plant for more fragile crops, as it provides a wind barrier and shade for lower-growing crops, so be sure to position it in the garden to help your other crops thrive. It has traditionally been grown with climbing beans and pumpkin – known as the ''three sisters" – as sweetcorn provides support for the beans to climb and the pumpkin smothers weeds across the bare soil.

Reaping the rewards of your hard work is really rewarding, but you need to know the right time to harvest your homegrown sweet corn in order to get the best-tasting cobs.

You will know when your sweet corn is perfect for picking when its end tassels turn dark brown. If you are uncertain as to whether the tassels are the correct colour, you can also determine the ripeness of your sweet corn by peeling away the skin of one of its kernels and puncturing it with your fingernail. The liquid that comes out should be creamy in consistency, rather than watery or nothing at all.

Harvesting your sweet corn is a process of simply twisting the cob and pulling it out. The freshness of your cob is at its highest right after harvest, so be sure to enjoy it as soon after harvesting as possible.