When to plant corianderin Perth.

Growing coriander in Perth: the specifics

Perth has a classic Mediterranean climate, hot, dry summers and mild, wet winters, giving it a completely different growing rhythm to the east coast. The long, dry summer (November-April) demands water-wise gardening and heat-hardy varieties, while the cooler months from May to October are Perth's prime growing season. Perth's warm winters mean brassicas, leafy greens, and tomatoes can all produce through the cooler months without frost damage. For coriander, the productive window in Perth is march-october (avoid midsummer). Within that window, Coriander's legendary tendency to bolt, sending up a flower stalk and going to seed rather than producing leaves, is its defining characteristic and the main challenge for gardeners. Understanding what triggers bolting allows you to manage it successfully. Bolting is triggered by long days (day length above 14 hours), high temperatures, drought stress, and root disturbance. This means: sow coriander in autumn, winter, and spring (not summer); water consistently; and direct sow rather than transplanting, as root disturbance reliably triggers bolting. Crush the seeds slightly before sowing, each 'seed' is actually two seeds in a husk, and cracking the husk improves germination rates. Sow 5-8mm deep in rows 20cm apart, thinning to 10cm spacing. Broadcast sowing in a dense patch works well for cut-and-come-again harvesting. Choose bolt-resistant varieties for maximum leaf harvest: 'Santo', 'Calypso', 'Leisure', and 'Confetti' resist bolting significantly longer than standard varieties. Succession sow every 3-4 weeks through the cool season. Rather than fighting bolting, many experienced gardeners embrace it, allow some plants to fully seed, saving the dried seeds (coriander seed is itself a valuable spice) and allowing self-seeding. Self-seeded coriander often germinates in exactly the right cool conditions for success. Grow coriander in partial shade in spring and autumn to extend the harvest before hot weather triggers bolting.

Sizing it for your household

Maintain 6-10 plants at various stages with 3-weekly succession sowing for continuous supply Ongoing (variable), a thriving plant produces 50-150g of leaves before bolting. Plant Planner does this maths automatically once you tell it your household size, it’s the part most planners get wrong because they assume every household is the same.

The 10 cm spacing (with 20 cm between rows) means a standard 1.2 m × 2.4 m raised bed in Perth can hold 144 coriander plants at maximum density, though in practice you’ll want to mix companions in, so plan for roughly 60-70% of that.

Companion plants for Perth

Good companions for coriander include Spinach, Lettuce, Dill, Tomato. In Perth’s mediterranean/temperate climate, these pairings reduce pest pressure and improve pollination. Keep coriander away from Fennel, they fight for the same nutrients or attract shared pests.

Perth-specific tips

• Perth's dry summers require drip irrigation or soaker hoses rather than overhead watering, conserve water and reduce fungal disease risk simultaneously.
• Unlike east coast cities, Perth's best tomato planting window is actually August-October for a summer harvest, with a second planting possible in late February.
• Perth's Mediterranean summers are too hot and dry for most leafy greens, focus on heat-tolerant herbs (rosemary, thyme, oregano) and water-efficient crops like sweet potato in summer.

Common problems

Bolting is the primary 'problem', manage with variety selection, succession sowing, cool temperatures, consistent moisture, and direct sowing. Powdery mildew occurs in humid conditions, ensure airflow. Aphids occasionally attack; treat with water blast or insecticidal soap. Leaf blight causes brown, water-soaked lesions in wet conditions, improve drainage and airflow.

Harvest

Harvest coriander by cutting stems at the base, taking no more than one-third of the plant at each harvest. When plants begin to bolt, pinch out the central flower stem to delay the process slightly, though eventually the plant will succeed. Once the plant has fully bolted, allow seed to mature, then harvest seed clusters. Dry and store seeds for cooking or future sowing.