After tomatoes, sweet corn may be the most popular crop grown in many family gardens.
However, as popular as it is, growing corn presents some difficult choices, mostly having to do with what other crops you will have to leave out.
In the limited space of a family garden corn is a poor choice if you are trying to maximize your garden yield, because one corn stalk only produces one or two ears, while a vertically-grown tomato plant taking up the same space can produce 10 to 20 POUNDS of tomatoes. Even a cabbage plant can produce 2 or 3 pounds in 2/3rds the time most corn requires to mature.
You can maximize your production of corn by planting close together in two rows per bed, and planting several short parallel rows, rather than one long one, because corn is pollinated by the wind carrying pollen from the tassels to the silks, and most comes from neighboring plants.
Build your garden using 18”-wide level, slightly raised beds with 4”-high ridges, and plant seeds or transplant seedlings 8” apart in the row, with rows 12” apart in the bed. Plant at the base of the ridges, rather than on the ridges. And aisles should be 3’ wide.
Because corn is considered a TENDER crop planting should not be done until AFTER the average last Spring frost date. Using early varieties can improve that somewhat, but even earlier and better results can be achieved by growing seedlings in a protected environment and transplanting strong, healthy seedlings into the garden on the date you would otherwise plant your seeds.
Transplanting seedlings also assures that you have 100% crop coverage, further maximizing your yield. This can be a big factor to consider, as cold weather, too-wet soil, bugs, diseases, birds, and other pests can substantially reduce the percentage of seeds that survive to become healthy seedlings.
Do NOT try to use the seeds from hybrid corn you’ve grown, since hybrid seed will be different than the parent seed, and usually produces inferior plants and ears.
Hybrid varieties have been developed in recent years that give us our choice of white, bi-color, or yellow corn, and are very high in sugar content. And the double and triple-sweet varieties will retain their sugar for several days after picking, if they’re refrigerated.
Hybridization has also produced corn with different maturity times, as well as frost and heat tolerance. This means that some varieties can be planted fairly early in the spring to give a June/July crop, and others planted later will mature between August and October. Later varieties are usually sweeter.
To maintain the sweet quality of the corn you are planting, isolation is recommended to prevent cross-pollination with other types.
When isolating corn there are four things you can do, separately or in combination, to minimize cross-pollination. Farmers often first consider distance, then time. Other considerations include barrier rows and wind direction.
For the home gardener it’s more important to isolate by TIME rather than by physical distance, barriers, or avoiding wind.
TIME ISOLATION – The home gardener rarely has sufficient space to avoid cross-pollination of corn. It’s much easier to determine the days to maturity and then plant two to three weeks before or after, so the pollen from one variety is not in the air during the time silk from another variety is receptive.
Once pollen is released from the tassel it is viable for about 24 hours, so avoiding that time period is critical. And the tassels from one planting can continue producing pollen for up to two weeks, so a minimum of 14 days should separate the tasseling time of the different types.
DISTANCE – Plants that are 12 feet apart may have as much as 50% cross-pollination, and cross-pollination of 1% requires separation of anywhere from 50 to 660 feet, depending on whose studies you believe.
BARRIER ROWS – Much of the contaminating pollen can be diluted by planting several rows of a different vegetable between varieties of corn. For this to be really effective the rows must be tall and constitute a real barrier, such as pole beans, vertically-grown tomatoes, etc.
WIND DIRECTION – By not planting different varieties of corn down-wind from each other isolation can also be improved.
If you can’t wait the requisite two weeks between plantings, the other three factors can be used to limit cross-pollination as much as possible.
Corn should be picked while the liquid inside the kernels is milky. Waiting too long will result in the sugar turning to starch and a considerable loss in the sweet flavor. Refrigerate as soon as possible to slow the sugar’s conversion to starch.