Spring Onion · Canberra, ACT
A local how-to for Canberra’s cool temperate climate, the planting window, the spacing, the pest pressure, and the family-of-four quantities. Built for raised beds.
The local entry
Plant spring onion in Canberra august-april.
Climate: Cool Temperate · Spacing: 5 cm · Days to harvest: 60-80 days · Sun: full
Planting window
August-April
Spacing
5 cm
15 cm rows
Sun
Full sun to partial shade
Water
Regular
Growing spring onion in Canberra sits inside a specific window, august-april, and the success of the crop hinges on respecting it. Canberra's cool temperate climate runs winter lows of about 1°C and summer highs around 31°C, with frost risk: April-October (regular frosts; heavy frosts June-August). Those numbers are the ones every Canberra gardener already knows by feel; they're the reason why the same crop behaves differently in a Sydney raised bed compared to a Hobart one.
Start with the bed itself. A raised bed of at least 30 cm depth gives spring onion room for roots to extend, and in Canberra, that depth also buffers the soil temperature against the swings that catch out shallow planters. Work compost through the top 20-30 cm until the bed mix is loose and friable. Target a soil pH of 6.0-7.0, which is the band spring onion prefers. If your Canberra water is alkaline (which it often is on the mainland), add a handful of sulphur or composted leaves to nudge the pH down. See our raised bed calculator if you’re sizing the bed from scratch.
Canberra's last frost is typically around late September-early October, never plant frost-sensitive crops (tomatoes, beans, zucchini) outside before mid-October.
Space plants 5 cm apart, with 15 cm between rows. A standard 1.2 m × 2.4 m raised bed in Canberra holds up to 384 spring onion plants at maximum density, though in practice you'll plant 60-70 percent of that to leave room for Carrot and Lettuce. Full sun to partial shade. Regular, keep consistently moist. If you want the full plant-by-plant spacing reference, the plant spacing chart is the printable version.
Spring onions are the workhorses of the raised bed garden, compact, fast, and multi-purpose. They can be grown as a long-term crop (pulling individual plants as needed) or as a short-term succession crop for continuous harvest. Sow seeds 1-2cm deep in rows 15cm apart, with 5cm spacing within rows. Alternatively, buy bundles of seedlings at the nursery and plant them directly. Spring onions tolerate close spacing well and can be grown more densely than most vegetables without competition.
In Canberra's cool climate, the constraint on spring onion is the short frost-free window, not pest pressure. Thrips cause silver streaking on leaves and can spread iris yellow spot virus, control with spinosad spray or reflective mulch. The bigger Canberra-specific risk is a late frost catching tender seedlings after a warm week tempts you to plant out too early, keep frost cloth on hand from April through October and run a soil thermometer before the first transplanting.
Good companions for spring onion in Canberra’s climate include Carrot, Lettuce, Tomato, Beetroot. These pairings reduce pest pressure and improve pollination. Keep spring onion away from Beans, Peas because they fight for the same nutrients or attract shared pests. The full matrix lives in our companion planting guide.
When it comes to the harvest itself, Pull individual plants when they reach pencil-width or thicker. The entire plant is edible, white bulb, green stem, and even flowers. For a continuous harvest, pull alternate plants and allow the remainder to continue growing. Wash and use immediately or store upright in a glass of water in the fridge for up to a week. Expect around 1 plant per harvest; regrows 2-3 times after cutting. For a Canberra household of four, Maintain a row of 20-30 plants at various stages; succession sow every 3-4 weeks
Canberra gardeners tend to do their best work when they stop treating the year as one long growing season and start treating it as a series of windows. The window for spring onion in your climate is august-april, set a reminder for the weekend before it opens, get the seedlings in, and the rest is just looking after them.
Canberra record
The numbers above sit behind every recommendation on this page. They’re the same climate signal Plant Planner reads from your postcode, see frost dates by city for the longer view.
Plant spring onion in Canberra august-april. Use a raised bed at least 30 cm deep with compost-rich mix, space plants 5 cm apart in rows 15 cm apart, give it full sun to partial shade, and water consistently. Expect 60-80 days from planting to first harvest.
In Canberra (cool temperate climate, frost risk: April-October (regular frosts; heavy frosts June-August)), the productive window for spring onion is august-april. Within that window, planting in the first two weeks gives the longest harvest tail.
Maintain a row of 20-30 plants at various stages; succession sow every 3-4 weeks Expected yield per plant: 1 plant per harvest; regrows 2-3 times after cutting. Plant Planner runs this calculation against your exact household size when you sign up.
Good companions in Canberra include Carrot, Lettuce, Tomato, Beetroot, Strawberry. These pairings reduce pest pressure and improve pollination in Canberra's cool temperate climate. Keep spring onion away from Beans, Peas, they compete for nutrients or attract shared pests.
Full sun to partial shade. In Canberra's cool temperate climate, you want every hour of sun available, especially during the cooler shoulder seasons.
Thrips cause silver streaking on leaves and can spread iris yellow spot virus, control with spinosad spray or reflective mulch. Onion leaf blight causes elongated lesions with dark borders, improve airflow and avoid overhead watering. Downy mildew appears as pale patches with furry growth, remove affected material. Snails and slugs eat young plants; use iron-based bait.
Tell us your postcode, family size, and the size of your bed. The planner runs the maths, lays out the bed, and emails you the planting reminders when the weekend before each task arrives.
Start free for two bedsNo card needed.