Time to scratch out your patch
THERE are about 450 species in the onion ( Allium cepa) tribe, although most are ornamentals. The edible varieties include leeks, garlic, common white, brown or red onions, shallots, potato onions, bunching onions, spring onions, chives and even “tree” onions.
Most can be planted or sown in winter. In fact, onion seed will germinate at temperatures as low as 2C. Most prefer a cool start with an increasing day length, which is why June and July are perfect months to start a crop.
Onions love a sweet, well- limed soil, so sprinkle a good double handful of limestone over every square metre of surface and rake it in.
Onions are great sources of vitamin C, B6, potassium, calcium; traces of selenium, zinc and folic acid.
They add flavour to most savoury foods yet contain little fat. Raw or cooked, onions are a natural health food and in Tasmania they can be grown to perfection.
Long- keeping onion varieties for sowing or planting now include Australian brown, Creamgold and red onions.
To create an onion bed, you need to cultivate and rake the soil, working it to a fine tilth. Get rid of weeds and their roots, then walk over the bed to firm it and rake the surface gently to leave a thin, even layer of loose soil. Onions love this firm base because it provides leverage as the swelling bulbs gradually thrust themselves from the soil. They need to be exposed to sunlight to fully ripen in late December.
Press a straight garden stake into the loose surface to make shallow grooves or drills, spaced about 20cm apart.
Onion seed is small, black and angular. For easier sowing, place a cup of fine, dry sand into a screw- top jar with a finger- sized hole in the lid and empty in a packet of onion seed. Shake to mix seed and sand so the mixture can be poured through the hole along the drill. The onion seeds should then be evenly spaced.
Don’t bother backfilling. Give the bed a good watering and keep the soil moist until germination happens in about two weeks.
Good onion seedlings are cheap. Don’t waste your money on lanky bundles of overgrown seedlings. These old seedlings tend to bolt uselessly to seed around November. Small seedlings in punnets are best – even tiny ones which still carry the black remnants of seed coats clinging to leaf tips.
To plant onion seedlings, make grooves deep enough to hold the roots. Carefully remove seedlings from punnets and wash off all soil to expose masses of white roots. Disentangle individual plants by gently pulling them apart.
These seedlings must never be deeply planted. Only the roots should be buried and if they fall over it’s no big deal because they soon pick up after a week or so.
The easiest way is to place out the seedlings flat on the ground 20cm apart so the roots dangle in the grooves. Then use a rake to carefully cover all the roots with soil. Water gently to avoid disturbing the seedlings.
These young plants gradually become upright as the roots take hold and are usually fully erect and growing strongly in two weeks.
Several seedlings can also be planted together in clusters, each group being about 15- 20cm apart. This method is ideal for container growing because they take up little space. As the onion bulbs swell, they simply push each other apart to allow large clusters of mature onions to be harvested.
Shallots are small, mild onions. They can be sown as seed or bought as bulbs at garden centres.
Don’t bother trying to grow imported supermarket shallots because they are usually heat- treated so they cannot sprout.
Shallot bulbs are pushed into the soil so only the necks are showing. They quickly form roots and by harvest time around Christmas, there can be as many as 10 to 15 new bulbs ready for eating or storing.
Onions grown in heavily fertilised soil grow too big and being soft, they’re relatively tasteless.
They don’t store well and quickly turn mouldy. The best fertiliser in average soil is sulphate of potash, sprinkled the rate of a tight fistful per square metre over the bed every month. This helps counter any excess nitrogen in the soil.
Onions are ready to be harvested after the leaves die and fall over naturally.
Never try to hasten ripening by bending the leaves. Harvested onions keep in good condition for months during summer and autumn when tied into strings and hung under cover or placed on wire racks in an airy place.