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vegetable growing techniques
corn
general information on corn
General characteristics
Corn is a large plant that needs plenty of space if it is to grow decent sized ears.  Planting distances vary slightly depending on what vegetable gardening book you are using.  A typical distance would be 2.5 cm (1 ") deep with plants 30cm (12 ") apart in each row and 75cm (30 ") between the rows.

It requires a rich well drained soil with a slightly acid to neutral pH.  Corn planted in very alkali soils is likely to suffer from a zinc deficiency, which can cause stunted growth.

Corn requires plenty of sunlight and heat.   It is also very susceptible to frosts at any stage of it's growth so it should only be planted after the risk of frost has passed.  It is usually ready for harvest within  twelve weeks of planting.


Pollination
ILLUSTRATION - Corn in a single row
If corn is grown in a single row at right angles to the prevailing wind then most of the pollen will be blown away from the corn.

ILLUSTRATION - Corn planted in a group
If you plant corn in a block you will maximise pollination rates.
Corn requires cross pollination, IE pollination from one corn plant to another. 

It is also wind pollinated, meaning that the pollen is blown from the male flower (the tassel) to the female flower (the ear with it's sticky silks).  This means that corn is generally harder to pollinate than insect pollinated plants. 

To maximise pollination it is best to plant corn in a block rather than a single row, that way the pollen is more likely to be blown onto  neighbouring corn plants.  This is especially so if a single row of corn is planted at right angles to the prevailing wind.

You will know if the corn has not pollinated properly as some or all of the corn kernels will not swell up.

planting
It is best to sow corn directly into the ground.  While corn can be grown in seedling punnets and transplanted out it doesn't transplant as easily as broccoli, cabbage, cauliflower or lettuce seedlings.  If you are planting corn seedlings then it is best to grow them in single cell seedling trays as seedlings grown in these trays suffer less damage to their root structures when being transplanted.


water requirements
Corn requires moderate amounts of water.  More than plants such as onion, garlic or tomatoes but less than celery, capsicum or pak choi.  It needs extra water when the corn ears are swelling.


pests and diseases
Corn is a relatively hardy plant.  It  is susceptible to slug and snail attacks when small but once the plants have reached a height of around twelve centimetres (8 ") slugs and snails are usually not a problem. 

Sometimes maturing corn cobs are attacked by the Corn Earworm caterpillar.    These caterpillars tend to only damage the tops of cobs.  The caterpillars  can be removed by hand or killed with derris dust.  If your corn cobs have been attacked by Corn Earworm caterpillars then just cut off the damaged part.  The rest of the cob is still quite edible.

There are a range of other pests and diseases that attack corn but in over twenty years of growing corn slugs and snails and Corn Earworms are the only pests that I have had to deal with.



Modified 2016-11-25