Our first crop of sweetcorn this year, sown on 30 April, was a great success. We grew a variety called Lark, which has given us excellent results three years in a row now. As with almost all readily available varieties, this is an F1 hybrid. Sweetcorn is one of those crops for which it is actually quite difficult to find an open pollinated variety, and one of the few hybrids that I still grow, although I am hoping to remedy that. One of the drawbacks of the hybrids, at least for the home grower, is that they tend to become ready to harvest at the same time. Whilst this may be advantageous for the commercial grower, who wants to mechanically harvest an entire crop at one time, it is rather the opposite of what the homegrower typically needs. Thus, we enjoyed delicious corn for a short period and then it was all over.
Rather late in the season – on 6 July – I decided to make a further sowing. The usual sowing time for corn is around mid April to mid May, so this was perhaps a bit silly. However, we were enjoying the first great cobs from our first sowing by 26 July – after approximately 12 weeks. I reasoned that there would be just enough time to get a crop towards the end of autumn, as the plants would germinate rapidly and grow away quickly in the warm sunny conditions. Assuming a similar sort of growth as the first crop, this would put the second harvest at the end of September to beginning of October, which indeed it did achieve.
So, then, what went wrong with this second sowing? They certainly started off well, germinating and showing their first leaves within just three days of sowing, and developing into sturdy young plants ready for planting in the polytunnel bed a couple of weeks later. Although the young plants were sturdy when planted, the stems did not develop quite the girth that they should, and then some of them started to bend at the node at which the cobs began to form. As the cobs developed, the angle of this bend became quite extreme, and had the effect of moving the pollen loaded tassels far away from the silks, no doubt contributing to rather poor pollination. Some hand pollination was attempted, but did not appear to be particularly effective.
The difference, apart from the sowing time, was that I only had to hand Kelvedon Glory, which is an older hybrid, and one I had not tried before. The first few cobs harvested were not too bad. They were rather small, nowhere near the size of Lark, even though Lark only produces medium sized cobs, but a few were quite well filled and the flavour was reasonable. Most cobs, though, were of a mean size and rather poorly filled. Few of the plants even attempted to form a second cob.
Perhaps the late sowing is partly to blame, but I suspect that Lark would have provided a good second crop. After all, there were sufficient weeks of good weather. In any event, I will not be giving Kelvedon Glory a second chance. I would like to try an open pollinated variety such as Golden Bantam instead – there are still one or two places from which open pollinated seed may be bought – perhaps alongside Lark, just in case, although if it does well, I would be quite happy to be free of hybrids. That said, Lark does give good tasting corn from robust, reliable plants.
I would also like to make two or three sowings next year, but none so late. Perhaps a first sowing mid April for the polytunnel, one a couple of weeks later for planting outdoors in early May, and then perhaps a second crop for the polytunnel sown around the end of May or early June. That would certainly spread the season.