Planted a few of these seeds in pots a few weeks ago and boy have they shooted up quickly - almost a 1/2 m tall. Too late to move them now but how high do they actually grow?

They grow quite tall and are ready dependant on whether you want baby corn or full size cobs. The stir-fry type (such as Minipop) are harvested before they are pollinated, as they're really just an immature form of cob. So they are harvested when the bits on the sides of the stalk have grown into a long bulge with the silky 'tassels' (look like pale green/whitish threads in a bunch) just coming out of the top. Whereas the ones you eat as 'corn-on-the-cob' must be pollinated. So these will grow long bulges on the side of the stalk, and the tassels will come out of the top, the pollen will drop down from the grassy bit on the top & stick to the tassels to pollinate the cobs. Eventually, the tassels will turn a chocolatey brown colour & your corn will be ready to harvest.

Let us know how you do, I tried growing corn a couple of years back but think that they didn't get pollinated or something as they grew to about 1m (they were a mini variety) but the cobs never formed