On 7 Aug, 07:59, Alan Johnson wrote:
We took our first sweet corn harvest yesterday. They tasted great, but
some of the cobs have what I can only describe as 'empty patches'.
Others are fine. Does anybody know what causes these empty patches on
the cob?

Incomplete pollination, or failure of pollen to 'take'. Each kernel
is separately pollinated down a very long fibre from the flower.
Pollination is wind-driven, hence planting in blocks not rows. The
upwind edge of the block can suffer like this easily enough, although
in the UK it is unusual for there not to be at least some time when
the wind is contrary to the prevailling direction. However, this year
the country was split in half and the eastern side had weeks and weeks
of southerly winds while the western half got atlantic airflow and
rains.

If the plants are under stress - too cold, not enough rain, for
example - then pollen production or take-up can fail or be seriously
reduced. If the male and female flowers do not overlap enough then it
can cause the symptom too, and this can happen if the weather gives
the plant a 'check' at the wrong time. I've heard of heavy dew
stopping pollen shedding or take up, but don't know any more about
that. The only thing you can sensibly do to influence pollination is
to keep the watering up in dry periods. I've heard of people
'shaking' the plants in windless periods, but I doubt this is really
necessary.