Sweetcorn is one of the best treats of late summer. Nothing is quite as delicious as freshly picked cobs, eaten raw, still warm from the sun. Sweetcorn has a reputation for being a risky crop to grow and older kinds did not do well in our short, erratic summers. But look for F1 hybrids, which are bred to be early to ripen and you can expect tasty crops in August and September.
You can buy plants or sow seeds and there is just about time to sow seeds this weekend. When buying plants never buy pots with crowded seedlings that need to be separated – buy them if grown in cell trays. You can sow seeds in cell trays yourself. Sow two seeds per cell and pinch out the weaker if both grow. You can even sow the seeds direct where the plants are to grow – two per station – but they need watering well and protection from slugs. It is easier to sow in cells and protect the seedlings and plant them out when about 20cm (8in) high.
A couple of points need emphasising. Each sweetcorn plant will produce one or two cobs – no more. And the cobs will only be full of kernels if they are pollinated. The pollen is produced at the top of the plants and drifts down to the female cobs. if you plant the sweetcorn in rows most of the pollen drifts off so you must plant them in blocks. You really need at least 25 plants, 5×5, to get a good crop and full cobs. This is not a crop where you can grow one plant in a pot and expect a decent crop! And because the plants need to be planted between 30-45cm (12-18in) apart, you need a fair bit of space.
On the positive side, you can grow other crops around the edge of the block such as quick growers like lettuce. Traditionally, in North America, sweetcorn, or more accurately maize (the same plant but grown for the mature kernels), is grown with French beans and squash which climb up and scramble below, the maize. It also looks great with sunflowers.
Keep the plants weed free and watered well to keep them growing fast. The next problem is knowing when the cobs are ready to pick. When the tassels on the cobs turn brown, peel back some of the ‘leaves’ around the end and press your thumbnail into a kernel. If the juice runs milky, then it is ready to eat. If it is clear then leave for another week. If left too long the cobs are still edible but will be tougher and less sweet.
Look out for bright red lily beetle and spray or try to remove them
Mow little and often. Avoid scalping the lawn by cutting too low, especially in dry weather.
Keep on top of weed in the garden, removing them before they set seeds.