Do not be alarmed, I know too well that it is cutting it a bit fine to start growing sweetcorn in mid May, that is partly why I have normal sweetcorn seed and seed for miniture sweetcorn too (like you get at the Chinese takeaway, lol!). The little ones are quite happy to be started this late as they don’t have to grow that big, we will see how the big ones go. I decided to start them off indoors and in two different ways. I have seen the use of vermiculite on BBC Gardener’s World a number of a times for seedlings and thought I would try with the compost on one side (a mixture of compost and vermiculite) and vermiculite only on the right hand side. For the vermiculite seeds I just put a sprinkling of them in the pot, put four sweetcorn seeds on top, and then put another small sprinkling on top of that. I watered it until I could see the vermiculite had changed a darker colour. This is all described in Mel’s book which I followed the instructions completly.
Just one week later and I am starting to see things happening, in the next 24 hours I would say we will have seedlings in both the compost and the vermiculite. Possibly then both methods are as good as each other, although this is no scientific test. The only advantage of the vermiculite route is that I have 100 litres of the stuff left over and it all needs using up!