When to plant onion in Sydney
Onion is cold-hardy, so every date keys off Sydney's frost dates.
Step 1 · Sow
Direct sow outdoors
Jul 10 – Jul 31
Sow straight into warm, workable soil.
Step 2 · Harvest
Harvest window
Oct 8 – Oct 28
Picking runs until conditions turn against the crop.
Window
Days to maturity
90 – 110 d
From sowing to first pick.
Common questions
When can I sow onion outdoors in Sydney?
Direct-sow around early July (Jul 10–Jul 31) in Sydney, based on its local frost dates. Confidence 82%.
When will onion be ready to harvest in Sydney?
Expect to harvest from around early October (Oct 8–Oct 28) in Sydney, based on its local frost dates. Confidence 76%.
How long is the growing season in Sydney?
Sydney has roughly 365 frost-free days, which is enough time to grow onion to maturity outdoors.
The rule of thumb
Sow onion as soon as the soil is workable — it tolerates cool weather and light frost. Every date on this page is derived from that rule and Sydney's frost dates.
Confidence 85/100 · Curated · based on NOAA GHCN-Daily 1991–2020 normal · frost dates are probabilities, not guarantees.