Corn Tips

There are many classifications of corn but the only one we stock is Corn with the botanical name Zea mays.
We stock Florida Supersweet and Honey & Pearl, both hybrids, imported into NZ by a fellow seed company.
All imported corn varieties must be treated with fungicide and insecticide.
This is due to the fact that corn is susceptible to an extensive range of insects, bugs, fungi and virus.
Any international seed supplier must be prepared to check for all of these and provide the appropriate documentation to pass NZ MPI import requirements.

Maintaining a supply of non-hybrid heirloom or open pollinated types is quite a challenge.
Those that we do stock are often varieties that we have grown ourselves.

Sowing and Growing:
Corn seed has a long shelf life as the seed is very dry with low moisture content.
To germinate, Corn likes:
Ideally 18+ degrees C for untreated seed, 16+ degrees C for treated seed
Under 16 degrees, you will achieve gradual germination
Under 13 degrees, NO germination

In October in coastal and northern areas
In November in inland and southern areas
In warm, rich, well drained and friable loams
Directly but also transplants well – will emerge in 3 to 22 days (7 days average)
In 4 x 4 blocks for better pollination – 30cm between the seeds and 1m between the rows and about 1” deep. If seed is sown too closely the resulting cobs will be smaller.
Isolated from other dry corn types – either 8m apart or 10 day difference in sowing time. If cross pollination occurs, kernels will be tough and starchy.
Using a one in every three years rotation. Never in the same place two years running.

Other notes:
If plants are flattened due to heavy winds, just stand up, stake and build up the soil around the plants. They will re-anchor.
Male part of plant is the flower head which will flick pollen over a great distance. You can improve pollination by “swishing” through a crop of corn to assist with this process.
Female part of the plant is the cob which forms from the silks. Each strand of silk equates to one kernel. All strands need to be pollinated to achieve a full cob of corn.
Harvest the cobs 18-24 days after the ear silks show – the silks will begin to dry and brown towards the end of this period.
You will only get one good cob per plant due to modern breeding.
You would need 11-17kg of seed per hectare.
Irrigate well from when the first silks appear to harvest time for juicier cobs.
Watch out for birds pulling out seedlings and use slug bait.
Florida Supersweet will last better on the plant than Honey & Pearl or heirloom/OP types.
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1 comment

Hi I sowed corn outside – which I see now is really stupid it was just after labour day in canterbury but we have had light frosts on and off for the two weeks after that. Do you think I could try to germinate it inside and move to the cold frame? We are 300m a above sea level so it might just still be a bit cold? I read your corn growing tips – when you mentioned temp was that day temp?

Rachel Lieuwes (Lieuwes/Abbott LTD PIC 2023)

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