That's a lack of pollination...corn is notorious for this. I hand-pollinate mine thoroughly now, with a huge difference in cob quality. Not on a windy day, if poss, so you can be more accurate!

Regards,

Shax

Thanks Shax, great to get such a quick response, I guess that's why they recommend to grow pumpkins with corn. I don't know if I'm that committed to growing good corn, the hand pollination sounds a bit arduos.
Regards Kirsten.

Hand-pollination is the best method but if you plant in groups and shake the plants early in the morning when the male flowers are full of pollen, you'll get a better pollination.
Rose-Marie

Hi Kirstenz
For good polination you need to have a lot of plants...the more the merrier.
It is also why planting in blocks rather than rows is recommended.
The tassles are the male flowers and they drop their pollen onto the silks of the cobs...each silk is connected to one kernal and so at least one pollen grain needs to land on each silk for germination to occur and thus the kernal to fill...rain and wind can affect good pollination...wind can blow the pollen away very easily and rain can stick the silks together so that some of them do not get pollinated
If you have few plants, then because the tassels form pollen a couple of weeks earlier than the silks appear, and the tassels only bear pollen for two weeks or so, you will find that late cobs may not get sufficient pollen to fill the cobs...this is even when the weather is great...so it pays to have a lot of plants.
You need to plant them fairly closely but not too close...plants 30cm apart will look great and will grow tall but will be spindly and prone to falling over because they become top heavy when the cobs form....they will then find it difficult to become pollinated ...these are only some of the problems that can occur and affect cob filling
Hope this helps...
cheers
Peter

3 years later...lol..I agree w/ Peter. Also too, most seed packets will tell you exactly how far apart to plant the corn. Usually 10-12" between plants, and 30" between rows is the norm. When your corn has good full tassels and the beginnings of ears, walk thru and shake the stalks, you'll get it all over you and the silks. Don't worry whether you hit them all or not...you did.

Next time you plant your corn skip the traditional rows and try this old farmer's trick: Imagine a single dice with the 5 showing. Plant the kernels like that about 4 inches apart and about 4 inches between each block. You get 15 kernels in 1 ft.
If you do that then put only a foot between another row, just like that. Plus you can pick from both sides just by reaching in instead of having to walk in the row and getting stuff all over you.
You can grow a lot in 5 ft if you do it right.