Corn can be grown hydroponically either indoors or out. Corn consumes a lot of vertical space, so that of course should be considered if planning to grow it indoors.
Anticipate that the corn stalks will reach seven feet in height. You’ll not only need the 7-foot clearance, but an adequate separation between the grow lights and the plants in order to avoid burning the plant tops if you are using overhead lighting.
If you don’t have the requisite clearance you’ll have to use side lighting, or if the season is correct move your plants outdoors when they approach their full stature.
Setting Up Your Hydroponic Corn System
Corn needs lots of light, 8 to 12 hours daily. Using side lighting with tall plants, such as corn is not quite as efficient as overhead lighting but it does work. With side lighting mylar or another acceptable reflective material, overhead is advisable.
A reflective surface in a hydroponic grow room optimizes the use of available light and decreases the need for expensive lighting, making it highly cost-effective.
Corn is wind-pollinated, it does not rely on insects for pollination, and hand pollination is not always feasible. With Corn, the pollen is transferred by the wind from the tassels to the corn silk at the end of each ear. A fan to blow the pollen around at the right times will be needed.
Once the corn produces tassels it is time to start the fans – gently – just enough to distribute the pollen from plant to plant – don’t blow it, or you’ll have barren stalks.
Hand Pollination, yes – not really practical, nor is it impossible. There are several methods – all time consuming.
The most basic hand-pollination method involves sniping off some tassel ends from each corn stalk, mix the tassels from different plants together in a bowl. Shake up the tassels and tap the bowl gently to separate the pollen.
You should be able to see yellowish dust, which is the pollen. Collect this pollen on the tip of a wet paintbrush or cotton swab, and gently transfer it to the corn silks. Be sure you are only using one type of corn – cross-pollinating corn, 999 out of 1000 times, produces garbage corn, corn that is starchy, tough and unpalatable, and best fed to chickens or pigs – not people.
See: Isolating Sweet Corn
Another method, which is helpful and relatively simple, although not as efficient, is to snip off a few tassels and walk around smacking the corn silks of the other plants with it. This alone won’t ensure pollination – but combined with a fan system will improve the odds in your favor.
Another factor relative to pollination to improve the odds is the placement of your plants. They should be arranged in a square or circular pattern – not in straight rows. A square or circle is much more effective than planting in rows for the purpose of pollination. it also uses your garden space more efficiently. A square formation ensures proper wind pollination no matter which way the fan blows. In a straight row a lot more pollen is blown where it is not needed.
Related: How to Grow Hydroponic Spinach
Corn can be grown in 5-gallon buckets at 2 stalks per bucket, or hydroponic tubs at 6 stalks per tub. I’ve been using a combination of both in order to make optimal use of available space.
A study conducted by by the International Symposium on Growing Media and Hydroponics concluded that coco coir is be superior to rockwool, increasing yields by nearly 20%. Coco coir mixed with clay pebbles, about half of each, is a very effective combination. It provides optimal moisture retention, nutrient control, and oxygenation near the root zone. This leads to increased nutrient uptake, a healthier plant and higher yield.
Seeds should be placed about an inch below the media surface. Anticipate germination in about a week.
Naturally, a small percentage of the seed will never germinate, if this is the case, you’ll want to replant more seeds in the empty spaces to ensure optimal use of your time, space, and resources.
Corn craves nitrogen, it should be fed on a nitrogen rich nutrient solution from seed to harvest. Moderate amounts of potassium and phosphorous for a balanced diet.
There are a number of signs which indicate when to harvest your corn. In the cornfield, Harvest is generally 18 to 21 days after the silk first appears. In a hydroponics setting, depending on conditions this process is somewhat expedited. Plants tend to grow up to 50% faster in a hydroponics setup. When all goes well – absolutely no glitches or setbacks – expect to harvest corn about 2 weeks after the first silk is visible.
Another sign is that the angle of the cob changes from being straight to around 30 degrees from the stalk.
And finally, to check for maturity you can peel back the husks for a peak. If the kernels look juicy stick a thumbnail in. The kernel will ooze a milky substance, somewhat like that in canned corn if it is ready for harvest.
At times I have harvested “baby corn” which is tasty, cob and all, not all varieties are suitable for this.
See – Baby Corn
Potential Disease Issues – fungal – Bacterial wilt – Mosaic, Corn Smut and Rust.