Sweetcorn
Zea mays
Sweetcorn is a tall annual plant grown for its sweet, juicy cobs. It thrives in warm, sunny conditions and must be planted after the last frost. Plants are wind-pollinated, so for best results grow them in blocks rather than single rows, ensuring well-filled cobs. With good care and warm weather, sweetcorn will reward you with delicious fresh corn-on-the-cob in late summer.
Growing Guide
Step-by-step instructions for growing Sweetcorn
Planting Calendar
1 Sow Seeds Indoors
Fill pots or modules with peat-free compost and sow one seed per pot about deep. Cover lightly with compost and water in gently (ideally from below to avoid disturbing the seeds). Keep the pots warm (around ) and moist. Start this indoors about 6-4 weeks before the last frost – around February in Wyndham – to give your sweetcorn a head start.
2 Harden Off
March in Wyndham is a good time to start hardening off the seedlings. Gradually acclimatise them to outdoor conditions by placing them outside during the day and bringing them back under cover at night. Do this for about a week, increasing their time outside each day. By the end of this step (around the last frost date) your plants will be toughened up and ready for transplanting.
3 Transplant Outdoors
Once all risk of frost has passed, transplant your sweetcorn outside. Choose a sunny, sheltered spot and plant seedlings apart in a block formation (not single rows) for good wind pollination. Firm them in and water them well after planting. Late March is an ideal time in Wyndham to get sweetcorn planted out.
4 Support and Water
About a week after planting out, start supporting and consistently watering your sweetcorn. As plants reach around tall, draw soil up around the base of the stems to support them (this helps brace them against wind). Keep the soil moist – water regularly at the roots, especially in dry weather – and consider adding mulch to conserve moisture. Well-watered plants will grow strongly and develop better cobs.
5 Fertilise
Feed your sweetcorn about 4 weeks after transplanting to boost growth. Use a high-nitrogen fertiliser (like general purpose feed or manure pellets) when plants are roughly knee-high. Repeat feeding as the tassels (male flowers) appear at the tops of plants. Providing extra nutrients at this stage helps ensure well-filled, juicy cobs. Always follow the fertiliser instructions for proper dosage.
6 Harvest Sweetcorn
Sweetcorn is usually ready to harvest by June in Wyndham, and you can keep picking into July as cobs ripen. Harvest cobs when the silky tassels at the end turn brown and shrivel, and the kernels exude a milky juice when pressed with a thumbnail. To pick, twist the cob downward and pull – it should snap off the plant. For the sweetest flavour, cook or eat the cobs as soon as possible after harvesting, before the sugars turn to starch.
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