To sow seeds into pots, fill a 7.5 cm pot with compost, and make a 2 to 3 cm hole with a dibber or the end of a pencil. Put two seeds in, cover and water. Leave the pots on a windowsill to germinate. Remove the weaker seedling when the growth of 2 cm has been achieved, and toughen your plants up in a shady location outside for a week before planting out.
To plant outdoors, dig out the intended bed deeply, mixing in well-rotted manure. Do this as early as possible – ideally the previous autumn. Closer to the time of planting, remove weeds and large stones, digging over the ground. Level the ground and rake over. Make individual holes for each plant and gently firm into the ground. Plant in blocks instead of rows, with 30 to 35 cm gaps between plants and roughly 60 cm between rows. Make the block as large or as small as you need. Use protective fleece in cooler spells when the plants are still vulnerable. Water regularly, especially once cobs begin to form. Sweet corn plug plants work well, transplanting easily and establishing quickly.