Cropedia:Sweet Corn
Sweet Corn
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Years grown at UBC Farm/LFSOG: On and off for 10 years/ None
Growing conditions
Corn will grow on most soil types but it may not necessarily mature at an appropriate time. Corn is a heavy feeder and it is recommended that adding manure or compost with fertilizer and mixing them thoroughly with the soil below seed furrow will provide the best results. Corn ear development is controlled by the amount of heat provided to the seeds. It is recommended that once sowing is complete to not water the soil as this will lower its temperature (Solomon, 2000). Seeds form and the tassel will appear once a corn plant has had an adequate amount of heat. Depending on the variety, a temperature of at least 15 degrees Celsius or higher is suitable for corn seeds to germinate, and even higher for sweet corn (about 18 degrees Celsius). Seeds will not germinate below temperatures of ~12.8 degrees Celsius (Johnny's Seeds, 2010).
Pollination occurs by wind-blown corn pollen. To ensure adequate pollination corn is planted in blocks of at least four rows wide by at least 10 feet long. Corn grows best when grown as single stalks far apart in rows as opposed to clusters. One plant spaced apart 10 inches in rows 30 inches apart is suffice (Solomon, 2000). Corn patches should be well watered until the tassels appear in which pollen can then be released. The tassel is the male pollen- producing flower of the corn plant and consists of stemmy flowers that grow from the top of the corn stalk (also known as the apex). Before a corn will tassel, it must grow a certain number of leaves within a 30 to 40 day period. Tassels will begin to grow once the majority of the corn stalk is complete. The pollen produced by the tassels must be wind- blown to reach the silks, otherwise known as the female flower of the corn plant. Once pollinated the ears of the corn are ready to begin growing (Johnny's Seeds, 2010).
Growing conditions for sweet corn vary compared to regular corn. The seeds of sweet corn are smaller than regular corn and tend to have more seeds per round. Sweet corn also requires twice as much moisture for germination than regular corn and should not be subjected to dry soil planting. Planting of seeds in a uniform depth and on the shallower side is also more important with this type. Harvesting sweet corn a few days late will not effect the tenderness and sweetness of the corn due to the plumper kernel grades. When the ear silks have begun to dry and brown and the kernels appear full and "milky", it is time to harvest the corn (Johnny's Seeds, 2010).
Seasonality
Generally sweet corn is grown between mid May and mid June. It can only be grown between the last spring frost and the beginning of the fall frost season due to its high sensitivity to frost (Solomon, 2000). The warmer the weather the earlier the vegetable will mature (Johnny's Seeds).
Nutritional Information
Sweet corn is an excellent source of nutrients particularily thiamin (vitamin B1), pantothenic acid (vitamin B5), folate, dietary fiber, vitamin C, phosphorus and manganese. A single cup of corn provides 19% of the daily value of folate, a B-vitamin that plays a significant role in cardiovascular health and fetal development(The World's Healthiest Foods, 2010).
It is also abundant in a carotenoid called beta-cryptoxanthin also found in pumpkin, papaya, red bell peppers, and peaches. Beta-cryptoxanthin is a provitamin with the ability to be converted into vitamin A. Recently this carotenoid has received much attention for its anti-aging and anti-cancer potential. Research has demonstrated a link between beta-cryptoxanthin and a lower incidence of lung and colon cancer (The World's Healthiest Foods, 2010).
In the presence of heat the sugar molecules within the corn kernels are rapidly converted to starch. To prevent loosing the sweetness and tenderness of the kernels it is recommended that corn be stored in a plastic bag in a cool place out of sunlight, such as the refridgerator. To retain the maximum amount of flavor of fresh corn remove the husk (leafy outer covering) only prior to cooking (The World's Healthiest Foods, 2010).
Nutrition Facts/Valeur Nutritive | |
---|---|
Serving Size: 1 Medium Ear of Corn (90g) | |
Amount Per Serving | %Daily Value* |
Calories 77 | |
Total Fat 1g | 1% |
Saturated Fat 2g | 0% |
Trans Fat 0g | |
Cholesterol 0mg | 0% |
Sodium 14mg | 1% |
Total Carbohydrate 17g | 5% |
Dietary Fiber 2.5g | 10% |
Sugars 3g | |
Protein 3g | |
Vitamine A | 0% |
Vitamine C | 10% |
Calcium | 0% |
Iron | 3% |
* % Daily value based on a 2000 calorie diet |
Note: Nutritional information derived from data provided by Health Canada.
Recipes
Corn Chowder with Chipotles
Corn chowder is often considered a comfort food. This dish has numerous variations suitable for everyone's taste! Soups like corn chowder make for a great lunch or dinner dish. A popular tend among local restaurants in Vancouver has been to use seasonal and locally grown vegetables in soups, salads, and stews providing customers with new and fresh dishes. Corn Chowder with Chipotles would be a great addition to any menu especially local restaurants like Rancity Grill, Pair Bistro, and Nu who pride themselves in their seasonal soups as well as their support for the UBC Farm. These restaurants feature various produce purchased from the UBC Farm on their menus (http://www.landfood.ubc.ca/ubcfarm/).
INGREDIENTS
3 strips smoked bacon
1 onion, chopped
2 cloves garlic, minced
2 stalks celery, chopped
3 cups chicken stock
2 medium potatoes, peeled and diced
1 sweet red pepper, diced
3 cups corn kernels
½ to ¾ cup whipping (35 %) cream (125 to 175 ml)
1/2 chipotle pepper (in adobo sauce), minced, or to taste
milk, to taste
coarse salt and freshly cracked black pepper
1 tablespoon chopped fresh cilantro (15 ml)
DIRECTIONS
Cook bacon in a large saucepan over medium-high heat just until crisp. Remove bacon and drain on paper towel. Set aside. Reserve 1 tbsp. of bacon in the saucepan and remove some of the bacon fat from pan and discard. Use the same saucepan to cook the chowder. Reduce heat to medium and add onion, garlic and celery to the saucepan. Sauté until soft, about 5 minutes. Add stock and potatoes and bring to a boil. Cover and simmer for 10 minutes, until potatoes are slightly tender. Add red pepper, corn, whipping cream, chipotle pepper and continue to cook for another 10 minutes or until vegetables are soft. Crumble reserved bacon and stir into soup. If chowder is too thick, adjust with ¼ cup of milk and just reheat until steaming. Season with salt and pepper and stir in cilantro. Serve.
Courtsey of Christine Cushing from Christine Cushing Live.
Additional Usage Inventory
Holiday wreaths can be made from the tassels of corn stalks, wire coat hangers, a hot glue gun, flora wire, and decorations.
Academic Connections
None so far
References
BC Ministry of Agriculture and Lands. (2010) Retrieved from http://www.al.gov.bc.ca/aboutind/products/plant/corn.htm
Corn Chowder with Chipotles Recipe. (2010) Christine Cushing from Christine Cushing Live. Retrieved from http://www.foodnetwork.ca/recipes/Soup/Pepper/recipe.html?dishid=4657
Johnny's Seeds. (2010). Sweet Corn. Retrieved from http://www.johnnyseeds.com/assets/pdf/Sweet%20Corn%2010GoldenRules.pdf
Solomon, S. (2000). Growing vegetables west of the Cascades : the complete guide to natural gardening. Seattle, WA: Sasquatch Books
The World's Healthiest Foods. (2010). Sweet Corn. Retrieved from http://whfoods.org/genpage.php?tname=foodspice&dbid=9
Additional Notes
- Corn is also known as Zea Mays and belongs to the Gramineae family. BC produces 18 million kilograms of sweet corn annually which constitutes about 5% of Canadian production. Three-quarters of the corn grown is used by the processing industry.
- Sweet corn, which is the corn that we eat fresh, is the result of a gene mutation that occurred sometime in the 1800s in the United States. As a result this mutation prevents the sugar in the endosperm of the kernel from being converted to starch thus increasing the sugar concentration per kernel and the sweetness (BC Ministry of Agriculture and Lands, 2010).
- The growth of corn is dependent on adequate heat such that the heat unit (HU) was developed to quantify the ideal heat conditions required for maturity. Heat units are calculated by summing the number of hours during a 24-hour period that had a temperature below 10 degrees Celsius then multiplying this number by the number of hours the temperature was above 50 degrees Celsius. To ripen, the earliest maturing sweet corn varieties required approximately 1300 HU; whereas, later maturing varieties may required more than 2200 HU (Solomon, 2000).
Lessons from the UBC Farm:
- Difficulty of Growing: 3 (on a scale of 1 to 5, where 1 is the easiest and 5 is the most difficult)
- Plant early using early maturing varieties and hope for a sunny hot summer as this crops needs copious amounts of sun. Sweet corn must be manually pollinated if growing a small numbers of plants (Tim Carter, UBC Farm Production Coordinator, personal communication, March 16, 2010).