There’s a particular Australian afternoon — the third day above 38, hot wind, the basil flat and even the natives looking philosophical — when gardeners discover that heat is a different enemy from drought. Drought is slow; a heatwave mugs the garden in hours. Getting through it is triage, and the order of operations matters more than any product.

The triage order

1. Water deep at dawn, not little and often. The single biggest lever. Water before sunrise so plants face the day fully loaded and moisture reaches depth before evaporation taxes it — the deep-watering method at its most important. In a heatwave the frequency rises (daily for beds under real stress, pots maybe twice) but the depth principle holds: shallow sprinkles in hot wind vanish before they matter. Evening top-ups for anything that flagged during the day are fine; dogma loses to a dying plant. And if water is racing off rather than in, your soil crust has gone repellent — the ten-second test and fix live in the watering guide.

2. Shade the vulnerable — temporarily. Emergency shade is stupidly effective: 30–50 percent shade cloth (the lighter grades — dense cloth steals too much light for edibles) pegged over stakes, an old bedsheet on tomato stakes, a beach umbrella over the hydrangea, shadecloth clipped to the trellis on the western side. Rig it before the worst day, aim it at afternoon sun, and remove it when the heat breaks — permanent shading is a different decision. Leafy greens, seedlings, hydrangeas, fuchsias and anything recently planted are first in the queue.

3. Move what can move. The container gardener’s superpower: pots migrate to the south side of the house, under trees, onto the shaded end of the balcony. Small dark pots in full sun are the first casualties of any heatwave — the pot-size and heat mechanics explain why the same plant in a bigger, lighter pot sails through. Hanging baskets come down; they dehydrate faster than anything on the ground.

4. Mulch anything bare — even mid-heatwave. A hand-span of mulch laid over just-watered soil drops the root zone’s temperature and halves its water loss for the rest of the event (what to use where). Ten minutes per bed, immediate payback.

5. Stop helping in the wrong ways. No fertilising during heat stress — feeding pushes growth exactly when the plant can’t fund it, and salts in dry soil burn roots. No pruning off scorched leaves mid-event — ugly foliage is now sun protection for what’s behind it; tidy up a week after the heat breaks. No transplanting, obviously. Benign restraint is a treatment.

Reading the plants honestly

Wilting at 3pm, perky by evening: normal defensive behaviour, not thirst — check soil before adding more water to an already-wet pot (heat wilt and drowning look identical from above; the finger settles it). Wilted at dawn: genuinely dry — water now, deeply. Scorched patches, bleached leaves: cosmetic sunburn; recovery pruning waits. Crisped seedlings: replant when the week ends — that’s what succession sowing is for, and it’s also why the herb list splits into the heat-proof and the doomed.

The bigger arc

Every heatwave audit writes next season’s plan: the bed that always cooks wants afternoon-shade planting or a shade-sail hook installed in comfort, the thirstiest pots want upsizing before December, and the garden that had mulch, deep roots and a shade kit in the shed treated the whole 40-degree week as weather rather than catastrophe. That’s the goal: not a heroic save every January, but a garden built so the save is barely needed. (Queensland’s other extreme-weather drill shares half this checklist — storm season prep.)