By: Ron Kushner
Corn (Zea mays) is truly an American native, cultivated for more than 4,000 years by a variety of civilizations. Sweet corn is the home garden favorite, either white, yellow or bicolor. To me, fresh corn on the cob is the essence of summer (along with a fresh picked ripe tomato).
You don’t need a huge amount of space to grow corn. A four foot by four foot raised bed will easily handle 16 stalks. Plant three different sections, if possible: End of May, Mid June, and July 4th. This succession planting will give you fresh corn well into the fall as you can usually depend upon two ears per stalk.
Corn is a cold sensitive crop and should not be planted until at least two weeks after the last frost date, which is May 15th in our area. The soil should be 60 degrees F before planting the seed. It is very susceptible to frost. It will not germinate at lower temperatures and could easily rot if spring weather is wet and cool. Seed should be planted directly in the garden as seedlings don’t adapt well to being transplanted. Seed generally lasts two years if kept in a cool, dry place.
Grow your corn in full sun. It is a heavy feeder, especially on nitrogen & likes a rich, well-drained soil. It is a good idea to enrich the soil the previous fall with lots of compost and if possible, a cover crop of beans, alfalfa or clover. Cut down the cover crop turn under and mulch before a hard freeze. In the spring, remove the mulch to allow the soil to heat up faster and apply more compost before planting.
Corn should be planted in blocks, rather than rows, with each seed about a foot apart in all directions so that there is no need to thin the plants later. This spacing will also promote complete pollination. In an early planting, sow seeds 1″ deep. Later plantings in hot weather should be deeper at 2″ to 3″. Control weeds by mulching well. The soil should be kept evenly moist but not wet. The plants should never dry out and should be watered especially well when tassels begin to appear. Water around the base of the stalks so as not to wash away pollen that would decrease your yield. Using drip irrigation is an excellent way to ensure adequate moisture. You can cover seeds with floating row covers supported by hoops to maintain soil temperature and protect seeds and seedlings from frost and birds. The cover can be removed once night temperatures are above 60 degrees. If you are planting different cultivars, you must keep them at least 400 yards apart to avoid cross-pollination.
Fertilize with a granular fertilizer when stalks are about 6″ tall and again when tassels begin to show. If using liquid, fish fertilizer, fertilize weekly for the first month. In order to produce kernels, the wind must deposit pollen from the tassels onto each of the silks on the ears. Every un-pollinated silk results in an undeveloped kernel. Don’t remove any side shoots or suckers. They won’t harm production and you could damage the shallow root system.
When ears begin to show, check leaves for holes and ears for tunnels through them which are signs of the corn earworm. This insect is an inch or two long yellow, green or brown striped worm. If the pest is showing, spray mineral oil, vegetable oil or neem oil on the tip of each ear. The oil will drown the worms. Make sure to apply the oil only after the silks wilt and start to turn brown. This condition indicates that pollination occurred. You could also spray “BT” (Bacillus thuringiensis).
Harvest the corn when the silks are brown and damp at the very ends and the kernels are plump and tender. To confirm an ear is ready to harvest, pull back the husk just enough to press a kernel with your thumbnail. If milky liquid squirts out, it is ready. To harvest, twist the cobs off the stalks. Pick corn in the early morning as this is when the sugar content is at its highest, then refrigerate in the husk until ready to eat.
After harvesting corn, chop up the stalks with a machete for faster composting. The smaller the pieces the faster they break down.
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