Sweetcorn Growing Guide

Sweetcorn Growing Guide

Delicious sweetcorn is a firm family favourite. If flavour and taste are important to you then you must try growing your own at home. Sweetcorn is at its mouth-watering best when eaten within hours of harvesting.


Sweetcorn is particularly easy to grow, and a good choice for small gardens as most of the space it takes up is vertical, not horizontal as with most other vegetables. What’s also great about sweetcorn is that it can be used as a support system for climbing vegetables like peas and beans.

Sweetcorn must have heat and sun to flourish. Young plants aren’t strong enough to stand up to frost, so in cold areas don’t even think about planting them outdoors until November. This isn’t too late as they take only three to four months to mature. Refer to our Planting Calendar for planting and harvest times in your region.

As corn is a tall crop, it needs protection from strong prevailing winds. Planting it against a sunny fence or beside a glasshouse is ideal. 

Sweetcorn favourites include the following varieties: Gold & Pearl, Honey & Pearl, Sugar Sweet and Xtra Tender.

If growing from seed, sow sweetcorn seed under glass or directly in rows once the soil warms. The seed must be fresh if it is to germinate.


Like building a house a good foundation is the key to success in your garden. The better the soil, the better your plants will grow. Sweetcorn enjoys fertile soil. If you are starting with an existing garden bed dig in organic matter like Tui Sheep Pellets and Tui Compost to your soil. Then you can add a layer of Tui Vegetable Mix. If planting in pots and containers, fill with Tui Vegetable Mix.

The best times to plant are early in the morning or late in the day, so the plants aren’t exposed to the hot sun straight away. Always water plants well before and after planting.

Planting in garden beds

Sweetcorn is wind pollinated from plant to plant so you don't want to plant them too far apart. It will depend on the variety you choose, but on average 50cm between plants seems to work well for most varieties. 

  • Water plants thoroughly before planting and allow to drain.
  • Dig a hole, approximately twice the depth and width of the root ball of your plant.
  • Partly fill the hole with Tui Vegetable Mix.
  • Gently loosen the root ball of your plant and position the plant in the centre of the hole.
  • Fill in with Tui Vegetable Mix.
  • Press soil gently around the base of the plant.
  • Water your plant well.

Planting in containers

Sweetcorn happily grows in containers or raised beds as long as there is enough room for its roots to anchor themselves into the soil - they need a soil depth of a least 30cm, ideally 50cm.

  • Water plants thoroughly before potting and allow to drain.
  • Partly fill your container with Tui Vegetable Mix.
  • Gently loosen the root ball of your plant and position the plant in the container.
  • Fill your container with Tui Vegetable Mix up to 3cm from the top.
  • Tap the container gently on the ground to settle the mix.
  • Press soil gently around the base of the plant.
  • Water your plant well.


Feed your plants and they will feed you. Plants use nutrients from the soil as they grow, so replenishing the nutrients ensures your plants grow to their full potential.

Select a fertiliser specially blended for your crop like Tui Vegetable Food. Feed sweetcorn planted in containers with Tui NovaTec Premium fertiliser. Keep the soil moist throughout the growing season.

Well watered, well nourished sweetcorn will have a better chance of keeping insect pests and diseases at bay. While your sweetcorn are growing regularly apply a dose of Tui Organic Seaweed Plant Tonic regularly to give them a welcome boost.

Staking may be required for taller plants or those grown in windy areas.


As the cobs develop, they sit very upright close to the main stem of the plant, and as they ripen they begin to move away from the main stem to allow the kernels room to ripen evenly. Once the cobs are sitting at around a 45 degree angle to the main stem, they are generally ready to harvest. Sweetcorn needs to be left on the plant to fully mature. Gently pull back the leaves on a cob or two and use your fingernail to check the ripeness of the kernels - the juice that comes out from the kernel should be milky.

Protect your plants from the elements with layers of Tui Pea Straw Mulch, to help keep their roots moist and keep your garden weed free.