Growing Onions

Latest Update 17th July 2016.

  • Onion seeds are sown in February in my garden and transplanted to an Ecobed in June.
  • They are a useful addition to our diet used with garlic in vegetable based soups and casseroles.  We like them when used with organic sage and breadcrumbs to make a tasty stuffing for poultry dishes, and we love their sweetness when used in a combo of suitable vegetables roasted with beef, lamb or pork.
  • Black aphids are the main pests attacking alliums in our garden.  They appear as soon as the weather starts to warm in late winter/early spring.
  • If they are caught early, a couple of foliar sprays of organic horticultural oil a couple of days apart is usually enough to stop them in their tracks.
  • Spray early in the morning to avoid killing beneficial insects, and avoid over spray of neighbouring plants for the same reason. 
  • Onions keep well for up to 9 months if dried and hung in bunches in a dark dry place. 
  • Variety:                                                    Australian Brown.
  • Family group:                                           Allioideae.
  • Crop rotation group:                                   Light feeders.
  • Garden bed type:                                      Garden Ecobed.
  • Recommended soil pH:                             5.5 - 6.5.
  • Minimum sun per day:                               4 hours.
  • Plant spacings:                                        100 x 100mm.
  • Weeks to harvest:                                     25 - 30 weeks.
  • Good companions:                                    Carrot, chamomile. lettuce. tomato. brassica. leek.
  • Poor companions.                                      Pea. asparagas.
  • Climate:                                                    Warm temperate.
  • Geography:                                               Southern hemisphere. 
  • This food is very low in Saturated Fat, Cholesterol and Sodium. 
  • It is a good source of Dietary Fibre, Vitamin B6, Folate, Potassium and Manganese, and a very good source of Vitamin C. 
  • More from nutrition
Growing Conditions: 
  • They grow best in full sun.
  • They need well structured rich organic soil.
  • The soil must be kept moist until the tops begin to die back in summer. 
Soil Preparation. 
  • Clear space for onions in May and apply a 60mm layer of thermal compost covered with 50mm of fresh straw mulch.
  • Leave for 4 weeks to build up worm and microbial activity before planting.  
Growing Instructions.
  • Sow onion seeds under cover in February.  Scatter the seeds on the surface of an organic seed growing mix in a punnet, and lightly cover them with sieved growing mix.. 
  • Soak the punnet for an hour in a tray containing 10mm of water (preferably rainwater).  The water will wick up into the soil without flooding it. 
  • Sink the punnet 15mm deep in a Eco Propagator.  This will keep the soil moist until the seedlings are ready to transplant.  Protect the seedlings against frost. 
  • After about 12 weeks, remove the young seedlings from the punnet and carefully separate them.
  • In the prepared bed, make rows 100 mm apart, and plant the seedlings at 100 mm centres along each row.
  • Make a hole for each seedling about 50 mm deep with a dibber (your finger will do) and hold the seedling in the hole so that about 20mm of the stem is below the surface.  Backfill with soil and water in with rainwater. 
  • Cover the soil with fresh mulch as soon as the onions are established.
  • Give them space to prevent other plants from shading them too much. 
  • Apply a foliar spray of aerated compost tea every 4 weeks with all the other edible plants.
Harvesting and Storage
  • Harvest the onions when the tops start to dry and fall over. 
  • Pull them out of the ground and rinse off the soil with water.  Leave them to dry in the sun for a few hours.
  • String the onions together in large bunches using the dried stalks and some twine to tie them together.
  • Hang them in a cool, dry airy place until ready for use.
Organic Pest Control. 
  • Aphids (blackfly).
    • You can use a jet of water to clear them off your affected plants, but unlike greenfly, blackfly seem to be able to climb up onto the plant again.  
    • Repeated applications will eventually remove them for good.Organic horticultural oil (Eco-oil in Australia) or a home made organic soap solution kills aphids by smothering them. 
    • Whatever you decide to use make sure you spray all the leaves and stems including the underside of the leaves. 
  • Slugs and snails.
    • Onions 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 approved iron based snail pellets as soon as you discover them.  You should only need to use a small number of pellets.
  • General:
    • Regular applications of aerated compost tea boost the natural defences of onions by colonising the leaf surfaces with beneficial microbes.  They defend the plant against airborne pests and diseases.
    • Similarly, proper soil preparation including regular applications of thermal compost boosts the community of beneficial microbes, which defend the plants roots against plant pathogens.
    • Exclusion netting stops birds digging up worms in your Ecobed.