Basic knowledge about the cultivation of maize.
When do we sow corn?
What are the sowing distances of corn?
Why do we sow several corns together?
How is corn pollinated?
What are the growth stages of corn?
These are some of the questions I will try to answer in this article.
Introduction to Corn – Maize
The scientific name of maize is Zea mays.
Maize is a member of the agrass family and has many characteristics in common with other cultivated grains such as wheat, rice, barley and others.
Although maize is a staple food source in many countries, its nutritional value is lower than that of other cereals. Also, bread made from corn in Greece, known as bobota, is not of good quality. Corn starch (also known as corn starch or corn flour) is used in confectionery, starch products and sausage making. In Latin America, corn is used as the base for a type of dough used to make tortillas, flat pies that replace bread.
Corn or maize or arapositi ( sitaros or sitaropoula in Cyprus) has the scientific name Zea mays.
The Greek scientific name of the plant is Arabositos the common It originates from the American continent where it was already cultivated 5,500 years ago by the Incas, Maya and Aztecs.
Its Greek name, “arabositos”, means “the wheat of the Arabs” and was introduced to Greece in 1600 from North Africa.
When to sow corn
In Greece we sow corn in the spring, 10 to 15 days after the last frosts in our area. Soil temperature is an important parameter as most maize varieties will not germinate if soil temperatures are below 10 degrees Celsius. When the soil temperature reaches 15 degrees Celsius, seeds germinate quickly and corn seedlings emerge from the soil in 7 to 10 days.
The sowing depth of corn seeds depends on the moisture in the soil. If our soil holds moisture high, then we plant the seeds at a depth of 2 to 3 cm.
If our soil holds moisture deeper, we sow the seeds even at a depth of 8 cm.
Corn needs a lot of water. Remember this.
What is the sowing distance of corn?
Sow the corn in rows. Never sow only one row. Sow as many rows as you can, close together. We’ll see why later and it has to do with the process of pollinating the corn. I am sure you have seen the fields planted with corn in Greece and America, with corn plants next to each other.
The spacing of the corn seeds in a row is 30 to 40 centimeters. The spacing between rows is from 50 to 100 cm.
For home cultivation, I would recommend that the distance between rows be close to 50 cm. The shading created by the plants reduces the rate at which the soil loses water due to evaporation. Also, because we are definitely talking about limited space, we want to make the most of it.
How corn is pollinated
Corn has both male and female fertilizing organs on the same plant. It is monoecious.
Tessel, the male inflorescence of corn
The male reproductive organs appear at the top in the form of a male inflorescence called a tessel. From this comes the pollen that will pollinate the female flowers.
Silk, the female inflorescence of the corn
The female inflorescence is called the silk and is located lower on the plant. It is easy to notice as it has the shape of a thymus that protrudes from the top of the ear. Inside the ear is what will become the corn we will eat. What is left of the ear when the corn is mature are the long brown fibers, what we call the “whiskers” of the corn.
Corn pollen on a corn leaf
For corn to be pollinated, pollen from the male inflorescence (tessel) at the top must reach the female inflorescence (silk) below. Each inflorescence produces 2 to 25 million pollen grains that are produced in anthers.
This is done naturally and with the help of the wind when conditions are ideal. And when are the conditions ideal? Usually twice a day. Between 9 and 11 in the morning when the morning humidity is gone, and in the afternoon. But it’s in the morning that we have the much larger, main, pollen release.
Detail of a tessel, the male inflorescence of corn. The anthers are visible.
Not all anthers release pollen at the same time. Usually this happens gradually over a 7-day period.
The pollen is carried by the air and some of it falls on the spadix (silk) of the female inflorescence below and fertilizes it so that the corn fruit (ear) begins to be produced.
Detail of the female inflorescence (silk) of the corn
Interestingly, only about 5% of a plant’s pollen will pollinate the plant itself. The remaining 95% tries to fertilize its nearby plants. That’s why we sow the corn close to each other. So they can pollinate each other.
Tip: If you have a few corn plants, you can use a paintbrush to take pollen from the male inflorescence and transfer it to the female inflorescence of the neighboring plants.
The silk of the pollinated female inflorescence will turn from white to brown until it eventually becomes the familiar whiskers.
Depending on the success of the pollination process, the more kernels the corn will have.
What are the stages of corn growth?
Experts divide the stages of corn growth into two phases. Germination and reproduction.
In the vegetative phase, we measure the growth of the plant.
In the reproductive phase, attention shifts to the stages of development and ripening of the kernels.
The vegetative phase is divided into 10 or 12 stages, where the number of leaves produced by the plant and the development of the inflorescences are measured. To avoid bogging you down with details that are not the goal of this article, you can see them in the following photo and the following article “Corn Growth and Development” from the Department of Agronomy in Kansas State University.
Stages of corn plant growth (vegetative phase)
The reproductive phase is measured in 6 stages, depending on the growth and ripening phase of the kernels.
R1 – Silk – one or more silks extends outside of husk leaves
R2 – Blister – kernels resemble “blisters” with clear liquid
R3 – Milk – kernels filled with “milky” fluid
R4 – Dough – inside the kernels are a “doughy” consistency
R5 – Dent – dent forms on kernel and milk line progresses towards kernel tip
R6 – Physiological maturity – kernels at maximum dry matter accumulation; a “black layer” will form at kernel base (2-3 days after physiological maturity)
Irrigation Fertilization of corn
You can find useful information on irrigation, fertilization, pests and diseases of maize in the following thesis ‘MAIZE CULTIVATION OF MAIZE IN THE PELLAS AND SERROS COUNTIES. PROBLEMS AND PROSPECTS‘ by KOLOKOTRONI ANASTASIA and TSIOMANI EVAGELIA, supervised by Professor Palato Georgios.