It's my first year growing sweetcorn and I believe that the corn is just about ready for picking when the tassels turn brown and a milky liquid is released on pressure from a thumbnail to the kernels. But my tassels are turning brown and dry already....the plants are beautifully healthy and the cobs swelling well but I am sure they can't be anywhere near ready yet!
So what is going on? why turning brown so early? I take it this can't be usual or it wouldn't be one of the signs to look out for....
The browning is because they are dieing off, having pollinated the grains... some modern varieties are quite quick to produce cobs. Mine haven't even put out tassles yet... :-\
It is the spider syndrome. Once the male has done his bit he dies off so the female can get the nourishment and produce.