Growing Sweetcorn

Latest Update 24th August 2017.

Sweet Corn
  • Sweetcorn is a variety of maize.
  • It is believed that it was originally cultivated in Mexico by the Mayans and other indigenous American nations.
  • It is a summer crop and grows well in a hot sunny climate.
  • I grow mine close together in a bunch to help with pollination.
  • I use climbing beans as companion plants as they provide useful nitrogen for the corn, whilst using the corn stalks as climbing supports.
  • The corn is earthed up as it grows to provide support for the plant against high winds in spring.
  • Corn needs to be used as soon as its harvested or stored frozen in the fridge.  If left uncooked or not frozen for any length of time after harvest, the corn loses its natural  sweet taste.
  • Binomial name:                                        Zea mays subsp. mays
  • Family group:                                           Poaceae.
  • Variety:                                                    Golden Bantam.
  • Crop rotation group:                                  Summer.
  • Garden bed type:                                      Ecobin.
  • Recommended soil pH:                             6.0 - 7.5.
  • Minimum sun per day:                              8 hours.
  • Plant spacings (centres x rows):                150 x 150 mm.
  • Weeks to harvest:                                     11 - 14 weeks.
  • Good companion:                                     Especially climbing beans, cucumber and pumpkin.
  • Climate:                                                   Warm temperate.
  • Geography:                                              Southern hemisphere. 
  • This food is low in Saturated Fat, and very low in Cholesterol and Sodium. 
  • It is also a good source of Dietary Fibre, Vitamin C, Thiamine, Folate, Magnesium and Phosphorus.
  • More from nutrition
Growing Conditions: 
  • They grow best in warm sunny conditions.
  • They are frost tender.
  • They need well structured rich, moist organic soil.
Soil Preparation.
  • Remove unwanted organic litter and old mulch from the surface of the soil in an Ecobin.
  • Add a 60mm layer of home made compost and cover it with 50mm of fresh straw mulch.
  • Leave the bed for 4 weeks to build up worm and microbial activity.
Growing Instructions. 
  • Clear spaces in the mulch in September and sow 4 seeds in each Ecobin.
  • Use your finger or a dibber to make a 15mm hole in which to plant each seed. 
  • Water them in with dilute seaweed extract (suppliers recommended dilution rate).
  • Move the mulch back into place, so all the soil is covered, once the corn is established and tie them loosely to a stake located in the centre of the Ecobin. 
  • Apply a foliar spray of aerated compost tea every 4 weeks when all the other edible plants are sprayed.
Harvesting and storage
  • Harvest the sweetcorn in January.
  • Pick them when the silky threads on the cobs turn brown or black
  • Use right away or preserve them in the freezer.
  • To freeze them, blanch the stripped cob in boiling water for 2 minutes and put them in your freezer in a zip bag. 
Organic Pest Control.
  • Slugs and snails.
    • Sweetcorn  should be protected against slugs and snails using self adhesive copper tape bonded around the base of your Ecobeds.
    • If these molluscs get into your Ecobed as eggs laid in your compost, kill them with organically accepted iron based snail pellets as soon as you discover them.  You should only need to use a small number of pellets.
  • Greenhouse whitefly.
    • Aerated compost tea strengthens the plants foliage against whitefly damage.  
    • Control any infestations by spraying your crop thoroughly with organic horticultural oil (Eco-oil in Australia).
    • Spray again in a few days to ensure second generation whitefly do not survive.
  • Powdery mildew.  
    • Spray the plant's foliage with aerated compost tea every month to keep powdery mildew at bay.
    • A solution of 1 part cows milk to 9 parts water makes a reasonably effective organic pesticide against powdery mildew.  However, it needs to be applied early before the fungi gets well established, and frequently to keep the mildew in check.
    • If necessary spray the plants foliage with organic horticultural oil (Eco-oil in Australia).
  • General:
    • Regular applications of aerated compost tea boost the natural defences of sweetcorn by colonising the leaf surfaces with beneficial microbes.  These microbes defend the plant against airborne pests and diseases.
    • Similarly, proper soil preparation including regular applications of home made compost boosts the community of beneficial microbes which defend the plants roots against pathogens.