We have been saving our own sweet corn seed for a few years now. It is easy to do and due to the fact that getting commercial open pollinated (non-hybrid) seed is impossible unless you go to one of the heritage seed suppliers like Eden seeds, Phoenix Seeds or Greenpatch Seeds, we need to maintain a supply. We don’t grow a huge amount of sweet corn but a couple of crops a year is nice and you can’t get corn any fresher or sweeter than the corn from your own patch.
To maintain genetic purity of your corn it is important to make sure that there is at least 500 metres between your crop and any sweet corn crop your neighbours might have or that they plant before or after you do so pollination won’t be happening at the same time. In practice the 500 metres is probably not necessary because corn is wind pollinated and a surrounding (unless it is a very close neighbour) crop is unlikely to be upwind from yours at just the right time. All of the buildings and other obstructions in the urban environment will also reduce the likelihood that your corn will be pollinated by their pollen.
Pick the juiciest, earliest cobs from your strongest, tallest plants and mark them (tying ribbon around them works) so that rather than eating them like you really want to, save them for seed. Leave them on the corn plant until the outer leaves are nicely dry and white. Then harvest the cobs and pull the outer leaves that protect the kernels back and hang them up out of mouse reach to let them dry out fully for a couple of weeks. Once the corn kernels are quite shrivelled and dry, you can remove them from the cob. I do this by giving the corn cob a Chinese burn, ie wrap both hands around the middle of the cob and twist each hand in different directions. The kernels should come away easily from the cob so once the removal has started just use your fingers to detach any remaining kernels from the cob.
To clean the seed, just drop the seed from one container to another in either a stiff breeze or in front of a fan, or while you blow on the stream of dropping seed. Any trash or silk will be blown away and you will be left with clean seed. I generally leave it in an open container for another two weeks or so to ensure it is fully dried out, then put it into paper envelopes or plastic bags for storage. Don’t forget to mark the variety of corn and the date harvested on the envelope or bag so you don’t forget. A couple of cobs worth of seed will net you enough to plant out a reasonable size back yard for at least one crop. Sweet corn will usually only remain viable in storage for a couple of years so grow your variety regularly and share it with your friends too.
