Cultivation of sweet corn: sowing, planting, harvesting

Description and Botany

Maize, the sacred plant of the Aztecs, is a plant native to Central America. Its cradle is located in central or southern Mexico, where it was domesticated by humans from teosinte (Zea spp.) over 9000 years ago. Its cultivation then spread across the equator. Maize was brought back to Europe by Christopher Columbus on his first return from America.

The common name Maize comes from Maiz, from the Taino, an indigenous ethnic group that occupied the Greater Antilles at the time of the Europeans’ arrival in the 15^th century. The genus name Zea was chosen by Linnaeus and refers to the starch plant in Latin.

There are numerous selections and cross-breeds of maize, among the most common are (non-exhaustive list):

• Sweet or sugar maize (Zea mays saccharata) grown for fresh consumption.
• Popcorn maize (Zea mays everta) grown for popcorn.
• Flint maize (Zea Mays indurata) grown for the milling industry.
• Dent maize (Zea mays indentata) grown for animal feed (fattening) and for starch.
• Modern selections of maize (flint x dent) are grown as grain maize (starch, biodegradable bags) and as forage maize (whole plant for animal feed).

Cultivated Maize (Zea mays subsp. mays) is an annual herbaceous plant of the Poaceae (grass) family. Variable in size, the stems measure from 50 cm to 4 meters high depending on the varieties. The stem is usually single but it is common for maize to produce secondary stems (suckers), which is referred to as tilling. These stems bear large elongated leaves at each node. The root system is shallow, consisting of numerous roots that appear at the base of the stem and descend up to 1 meter deep.

Maize is an anemophilous plant, meaning that pollination occurs via the wind, although bees are sometimes attracted to the pollen as well. A single plant bears both male and female flowers (it is said to be monoecious). The male flowers, shaped like panicles, are grouped at the top of the stem and produce millions of pollen grains that fall onto the silks (inflorescences of the female flowers) either by gravity or are carried by the wind. Pollen grains can travel up to 500 meters on average, making cross-breeding common. It takes about 2 to 3 months from sowing to pollination and another 2 to 3 months from pollination to the complete ripeness of the grains in the spike. Sweet maize is a special case as it is harvested about three weeks after pollination.

Male flowers at the top of the plant are laden with pollen; The silks of the female flower, each fertilised filament with pollen will produce a grain of maize; The formed spike

Sweet Corn Varieties

Sweet corn varieties

Other corn varieties

Ornamental varieties

Sweet Corn Golden Bantam

Golden Bantam sweet corn is an old variety originating from North America. It produces young plants 1.5 to 2 m tall and long pale yellow spikes with large sweet grains of excellent flavour.

• Flowering time July to October
• Height at maturity 2 m

See the product sheet

Sweet Corn Miner - Ferme de Sainte Marthe Seeds

Miner sweet corn is an early variety that produces medium spikes with sweet and tender grains. It is a variety better suited to mild regions due to its early ripeness.

• Flowering time July to September
• Height at maturity 1,50 m

See the product sheet

Sweet Corn Swift - Zea mays

Swift sweet corn is a variety with a sweet and sugary flavour, vigorous and productive, which will produce up to three spikes per young plant.

• Flowering time July to October
• Height at maturity 2 m

See the product sheet

Mini sweetcorn Snobaby - Zea mays

Snobaby sweet corn is an ideal variety for an early harvest of the spike. It can be consumed whole as soon as it reaches 5 to 10 cm in length.

• Flowering time July to October
• Height at maturity 2 m

See the product sheet

Corn Strawberry Popcorn - Ferme de Sainte Marthe Seeds

Strawberry Pop-Corn is a popping corn variety that produces small spikes of 5 to 6 cm with red grains. This variety, with young plants not exceeding 1 m in height, should be harvested at ripeness to make popcorn.

• Flowering time July to September
• Height at maturity 1 m

See the product sheet

Corn Tom Thumb Popcorn - Ferme de Sainte Marthe Seeds

Tom Thumb Pop-Corn is a small-sized popping corn variety, reaching 50 cm in height at ripeness. Due to its modest size, this variety is ideal for pot cultivation.

• Flowering time July to September
• Height at maturity 50 cm

See the product sheet

Corn Amarillo - Ferme de Sainte Marthe Seeds

Amarillo yellow corn is an old variety of corn, with large yellow grains rich in protein and starch. The harvest is done at ripeness, and they can be consumed cooked.

• Flowering time July to September
• Height at maturity 2 m

See the product sheet

Organic Multicoloured Maize - Ferme de Sainte Marthe seeds seeds

Multicoloured corn is an ornamental variety that produces long spikes of grains in various bright colours. It reaches 2 metres in height and decorates both the garden and the home.

• Flowering time July to September
• Height at maturity 2 m

See the product sheet

Zea mays japonica large varieties - seeds

This ornamental corn variety mix produces young plants 2 metres tall with long spikes made up of seeds in various bright and colourful shades. They can also decorate the home after harvest.

• Flowering time July to November
• Height at maturity 2 m

See the product sheet

Sowing maize

The sowing of sweet corn takes place in spring, between April and June. Its seed can be sown directly in the ground, in rows or in clusters of several seeds. The soil must be sufficiently warmed (12°C). In colder regions, sowing can be done in buckets, indoors, using seed compost and a bit of compost. The best young plant from each bucket will then be replanted in the ground around May-June.

Sowing in rows

1. Sow the corn in full sun after soaking the seeds in warm water for 12 hours.
2. Stretch a line and dig furrows a few centimetres deep (3 to 5 cm), spacing the ranks 70 cm apart.
3. Sow one seed every 10 cm.
4. Cover with fine soil and ‘firm’ lightly with the back of the rake.
5. After germination (about ten days), thin out to keep one young plant every 20 cm.

Sowing in buckets

You can start sowing in buckets, in warmth, as early as March, and you will plant them in May-June in the garden.

1. Sow 2 to 3 seeds 3 cm deep per bucket in seed compost.
2. Water regularly until germination.
3. Thin out to keep the best young plant per bucket.
4. Then plant in the garden from May onwards.
   

Association

Corn is the vertical pillar in the most famous of vegetable associations, the milpa, also known as the association of the three sisters. We owe this association to the Native Americans who cultivated corn in association with climbing beans and squashes. These three plants provide mutual benefits: a nitrogen residue from the bean (after harvesting), corn serves as a support for the bean, and the squash protects the soil with its large foliage, providing more freshness, creating a microclimate, and competing with adventive plants.

To create a milpa, in practice, first sow the corn in rows (at least 2 rows). When it reaches 10 cm in height, sow two seeds of climbing beans on either side of each corn plant. A squash (or courgette) plant is sown – or you may prefer planting – every 1 or 2 metres (depending on the expected growth of the variety) on either side of the corn rows.

Still rooted in culture in Central and South America, here is an association inspired by the milpa (legume + cereal): dwarf beans at the foot of the corn.

Cultivation and maintenance

Corn enjoys a sunny exposure and loose, rich soil: Add manure or compost during its preparation, for example in the previous autumn, to enrich the plot intended for sowing. The rotation between two crops of corn is about 4 years.

However, it is important to plant several rows of corn or to grow them in a square to promote good pollination. Indeed, the pollen from the male flowers (at the top of the stem) will fall onto the female flowers, located lower down on the stem. This fertilization can occur naturally with the wind or voluntarily by shaking the plants.

When the corn has reached about 30 cm in height, hill it up to 10 cm high to promote anchorage in the soil. Water regularly if it does not rain (once a week) but never on the male flowers during pollination. Cover the soil with mulch to retain moisture (grass clippings, straw…).

The right stage to hill young corn plants

Diseases and Pests

The corn borer

The caterpillar of the borer, a pest butterfly of corn, burrows into young corn spikes as well as sometimes the heart of the stems, causing them to break. As a preventive measure, shred crop residues before using them (for compost or mulching). Ensure good crop rotation by not growing corn in the same plot for at least 4 years. In case of a severe infestation, you can spray a solution of Bacillus thuringiensis, but this solution is not 100% reliable. Indeed, the caterpillars are protected by the sheath surrounding the spike.

The adult corn borer, but it is its caterpillar that damages the corn

Harvest and preserve

The harvest of sweet corn takes place approximately 80 days after sowing, depending on the heat and watering, when the silks begin to brown, about three weeks after pollination on average. The kernels should be well developed but still tender. To check if they are ripe, take a few from an ear and taste them. You can also squeeze them between your fingers; they should be slightly milky. If harvested too late, the sugar turns into starch and the skin becomes hard.

To preserve corn, after harvesting, remove the green sheath that envelops the ear, and consume quickly. To keep it longer, cook it and then store it in jars or freeze it.

1) Good harvest stage for sweet corn, the kernels are tender, milky inside, not mature 2) Good harvest stage for popping corn, the kernels are hard and mature[/caption>

Culinary Uses and Nutritional Benefits

Sweet corn is the fifth most consumed vegetable (cereal to be precise) in France. While canned corn is the most well-known and common, corn on the cob is much less so, except for gardeners.

Straight from the vegetable garden, sweet corn on the cob is excellent raw or just blanched for a few seconds in boiling water. For even more flavour, they can be grilled for a few minutes on the barbecue grill; grill them in their husks for added taste!

We can be grateful to the Native Americans who selected this cereal with its many health benefits! Sweet corn is rich in carbohydrates but its glycaemic index remains low, which limits the conversion and storage of carbohydrates as fats. It is rich in magnesium, fibre, and its beautiful yellow colour indicates its richness in carotene and antioxidants. It contains protein but is gluten-free. Finally, it is rich in vitamin B, which is good for the brain, helps prevent cardiovascular diseases, combats depression, and prevents osteoporosis.

Making your seeds

Sow only one variety at a time, or two varieties with staggered flowering: corn hybridises very easily and you would not harvest the sown variety. If your garden is located less than 400 m from a cornfield, the risks of hybridization are significant. This distance should be increased if your garden is situated in a windy area. However, be aware that natural hedges are relatively effective at protecting your varieties from unwanted cross-breeding.

It is recommended to force pollination by shaking the male flowers with a stick to drop the pollen onto the bristles of the female flowers. During flowering, the plant must not lack water for fertilization to occur properly.

Unlike harvesting for consumption, allow the sweet corn spikes to reach maturity for seed production. For sowing done in May, the harvest of mature spikes generally takes place in September or October.

Then let the spikes dry and wait until they are thoroughly dry before separating the grains from the spikes.