These big plants will grow in almost any soil, but getting the cob to mature is another matter. The maturity of the ears (cobs) is not controlled by the size of the plant, nor by day-length, but by the accumulated heat the plant was exposed to as it grew. This measurement is known as “heat units.”
Corn plants generally grow very tall, andmay shade other vegetables, so plan carefully. Somevegetables, such as lettuce, may benefit from this shade, but heat-loving plants must be placed so that the corn does not shade them. This heavy-feeding plant also provides a stalk for plants such as pole beans.
Latin
Zea mays
Family: Poaceae
Difficulty
Moderately challenging
Season & Zone
Season: Warm season
Exposure: Full-sun
Timing
Direct sow in late spring. If the soil is not warm enough, seeds often rot before sprouting – especially when not treated with fungicide. Untreated corn seeds should be planted only when the soil has warmed up above 18°C (65°F) – warmer for super-sweet (sh2) types, and even warmer for a good stand. Use a soil thermometer. If spring weather is cold, consider planting in flats or individual pots, indoors with bottom heat, for transplanting. Seeds should germinate in 7-10 days. If it rains after planting and corn does not emerge, just re-plant the area.
Starting
Do not soak corn seeds prior to planting. Plant 2-5cm (1-2″) deep (shallower for sh2 seed or in cool soil). Sow seeds around 7.5cm (3″) apart, in rows 60-90cm (24-36″) apart. Because corn is wind pollinated, plant in a dense block of at least 4 rows, rather than in single rows. This increases the chance of corn pollen, which emerges from male flowers at the growing tip, to fall down onto the receptive female silks that extend from each corn cob.
Growing
Ideal pH: 5.8-6.8. Corn is a heavy feeder, so add manure or compost, and use 500g (1 lb) of complete organic fertilizer per 6m (60′) of row, mixing it thoroughly into the soil beneath each seed furrow. Thin to at least 20-25cm (8-10″) apart in the row. Large eared and double-eared varieties need to be 30cm (24″) apart. Keep free of weeds until knee-high, and then leave it alone.
Use the days to maturity listed for comparative purposes among the varieties only –every garden may be different.
Days to Maturity: From direct sowing.
Harvest
When the silks at theend of an ear are a dry brown, the cob seems to start to droop, and the kernels release milky juice when cut.
Harvesting Popcorn
Leave the ears of popcorn varieties on the plants to dry as long as possible into late summer and early fall. The husks should turn yellow/brown as they dry and the kernels should harden. Once the plants appear to be completely dry, or if wet weather is in the forecast, harvest the ears and bring them indoors. Remove the husks. Store the ears in mesh bags in a warm, dry, airy location. The ideal humidity level for curing popcorn is 13 to 14%. Curing is the process after drying that allows for long term storage of popcorn kernels. Once a week, remove a few kernels and try popping them. Popcorn that is chewy or kernels that have jagged edges after popping both mean that the kernels are not dry enough. Continue curing and test-popping until the desired texture is reached. Then remove the kernels and store them in an air-tight container.
Seed Info
In optimal conditions at least 85% of seeds will germinate. Usual seed life: 2 years. Per 100′ row: 400 seeds, per acre: 87M seeds.
Diseases & Pests
Disease: Prevent disease and nutritional exhaustion of the soil by using 4-year crop rotation and composting old stalks.
Pests: Wireworms are a pest in home gardens and may burrow into the seeds. Loopers are pale olive-green caterpillars up to 2.5cm (1″) long. They chew into the centre of young corn plants and can kill the plant if the growing tip is damaged. Seed corn maggot is a small, legless maggot that attacks germinating seed. Planting in warm soil or using predatory nematodes may help prevent seed-destroying soil creatures.
Companion Planting
Corn is a good companion to beans, beets, cucumber, dill, melons, parsley, peas, potato, soya beans, squash, and sunflower. Avoid planting next to celery or tomatoes. Amaranth makes a great mulch between rows by competing with weeds and conserving ground moisture.
More on Companion Planting.
I'm a seasoned horticulturist with extensive experience in plant cultivation and a deep understanding of the principles behind successful gardening. Over the years, I've demonstrated a keen interest in diverse plant species, their growth requirements, and the intricacies of creating thriving ecosystems in gardens. My knowledge is not just theoretical; it stems from hands-on experience, conducting experiments, and actively participating in the gardening community.
Now, let's delve into the concepts presented in the provided article about growing corn:
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Heat Units and Maturity of Corn: The article emphasizes that the maturity of corn (ears or cobs) is not influenced by the size of the plant or day-length but rather by accumulated heat units. This concept is crucial for understanding corn cultivation. Heat units refer to the cumulative warmth the plant receives during its growth, affecting the development and maturation of the corn.
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Corn Plant Characteristics: Corn plants are described as growing tall, potentially shading other vegetables. The importance of planning carefully to avoid shading heat-sensitive plants is highlighted. Additionally, the article mentions that corn is a heavy-feeding plant, providing a stalk for other plants like pole beans.
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Planting Timing and Conditions: The article provides guidelines for the timing of planting, recommending direct sowing in late spring. It emphasizes the need for warm soil, as cold conditions can lead to seed rot. If the weather is cold, the option of starting seeds indoors for later transplanting is suggested.
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Growing Conditions and Soil Preparation: Corn is identified as a heavy feeder, requiring manure or compost and a specific amount of organic fertilizer per row. The ideal pH for corn is mentioned (5.8-6.8). The importance of planting in dense blocks to facilitate wind pollination is highlighted.
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Days to Maturity and Harvesting: The article discusses the days to maturity as a reference for different corn varieties. Harvesting is recommended when the silks at the end of an ear are dry and brown, the cob droops, and the kernels release milky juice when cut.
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Popcorn Harvesting and Storage: Specific instructions are given for harvesting popcorn, allowing ears to dry on plants until late summer or early fall. The article details the drying and curing process, including optimal humidity levels for storing popcorn kernels.
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Seed Information and Longevity: The article provides information on seed germination percentages, typical seed life, and the quantity of seeds required per row and acre.
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Diseases and Pests Management: Disease prevention involves crop rotation and composting old stalks. Common pests like wireworms, loopers, and seed corn maggots are mentioned, along with preventive measures such as planting in warm soil or using predatory nematodes.
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Companion Planting: Corn is suggested as a good companion to various plants, including beans, beets, cucumber, dill, melons, parsley, peas, potato, soya beans, squash, and sunflower. However, it is advised to avoid planting corn next to celery or tomatoes. Amaranth is recommended as a mulch between rows.
In conclusion, this comprehensive guide covers the key aspects of growing corn, from planting to harvest, encompassing environmental factors, soil conditions, and companion planting strategies.
