When to plant Mustard in Cool Australia

Cool zone — applies to Hobart, Canberra, Ballarat, Orange, Armidale and similar areas. Growing elsewhere? Temperate · Subtropical · Tropical · Arid.

Sow mustard direct year round in the cool zone, from January right through to December, as this hardy brassica handles cold well and grows fast in almost any season. Seed germinates in 6 to 12 days at 6 mm deep and plants mature quickly in 30 to 60 days depending on how large you let them grow. Space plants 30 to 40 cm apart with rows 40 to 60 cm apart, or sow thickly for tender young leaves. In gardens around Hobart, Canberra and Orange, mustard's all-season window makes it a dependable filler for both salads and green manure.

Sowing calendar — cool zone

Green months are your sowing window: January to December.

Growing notes

Mustard is about as easy as brassicas get, and its full January to December window means there is rarely a bad time to sow it in the cool zone. It is hardy, quick and useful in two ways: grown on for peppery leaves, or sown thickly and dug in young as a green manure to build soil between crops. Germination is fast at 6 to 12 days, and even the full-size plants are ready in 30 to 60 days.

Despite the year-round window, the warmest weeks are the weak point. Sown into hot, dry mid-summer soil, mustard bolts to flower quickly and the leaves turn coarse and fiercely hot. In the heat of a summer around Ballarat or Orange, keep the soil moist, sow into partial shade, and treat those crops as short-lived. The cooler months give the sweetest, most tender growth.

As a brassica, mustard can attract cabbage moth and aphids, though its speed usually keeps it ahead of serious damage. Watch too for flea beetle shot-holes on young leaves in dry weather. A light cover of fine netting over seedling rows keeps pests off without much effort. If you are growing it as green manure, cut and dig the plants in while still soft and before they flower, so the tissue breaks down quickly and returns the most nitrogen to the bed.

Mustard at a glance

Common questions

Can I really sow mustard all year in a cool climate?

Yes, mustard is hardy and fast enough to sow in any month in the cool zone, though the cooler seasons give the best, most tender leaves. Summer sowings work but bolt quickly, so keep them well watered and treat them as short-lived.

How do I use mustard as a green manure?

Sow the seed thickly, let it grow to a lush leafy stage, then cut and dig it into the soil while it is still soft and before it flowers. It breaks down fast, returns nitrogen and organic matter, and helps suppress some soil pests between crops.

Why is my mustard so bitter and hot?

Heat and stress sharpen the flavour and can push the plant to bolt. Leaves grown fast in cool, moist conditions and picked young are much milder, so favour the cooler months and harvest before flowering for the best taste.

Do I need to protect mustard from pests in Hobart?

Mustard is a brassica and can draw cabbage moth, aphids and flea beetle, but its speed usually keeps it ahead of serious damage in Hobart's climate. A light cover of fine netting over seedling rows is enough insurance for a clean crop.

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