The Autumn Equinox marks the moment when day and night are in perfect balance, but for the Australian gardener, it’s the ultimate "starting gun." As the blistering summer heat finally breaks, your polytunnel becomes the most valuable real estate on your property. It provides the stable environment needed to germinate winter crops while the soil outside is still cooling down.
Sowing in March allows your plants to establish strong root systems before the short, cold days of June arrive. Whether you are looking to fill your dinner plate with fresh greens or prep a commercial harvest, this is the window of opportunity. Here is our guide to what to plant right now to maximize your structure's potential.
Ready to start your autumn garden? Explore our premium polytunnels, plant supports, and greenhouse accessories to get growing.
1. The Brassica Powerhouse
Broccoli, Kale, Cauliflower, and Cabbage are the kings of the autumn garden. In many parts of Australia, planting these outside too early leads to heat stress or pest attacks. A polytunnel provides the controlled environment needed for consistent germination.
Starting these from seed in trays inside your Polytunnel allows you to monitor moisture levels closely. Once they have 4-6 true leaves, you can transplant them into their final positions. If you are growing taller varieties like Brussels Sprouts, ensure you have sturdy stakes ready to support them against autumn winds.
2. Fast-Growing Leafy Greens
If you want a harvest within 4-6 weeks, focus on Asian greens (Pak Choy, Tatsoi), Spinach, and Silverbeet. These thrive in the mild light levels that follow the Equinox.
Because these crops prefer consistent humidity, your polytunnel's ventilation is key. Our Polytunnel Pro Kit features large roll-up windows that let you flush out excess heat during a warm March afternoon while keeping the soil moist. For a continuous supply, try "succession planting"—sowing a new row every 14 days.
3. Root Vegetables for Winter Sweetness
Carrots, Beetroot, and Radishes are perfect for sowing right now. When grown under a 250-micron premium film, the soil stays warmer for longer compared to open garden beds. This extra warmth encourages faster root development.
Carrots, in particular, benefit from the protection of a polytunnel as it prevents the "crusting" of soil that can happen with heavy autumn rains, allowing the delicate seedlings to break through easily. As the temperature drops toward winter, the starches in these roots turn to sugar, resulting in a much sweeter harvest.
4. Herbs that Love the Shade
As the sun's angle changes, utilize the areas of your tunnel that receive dappled light. Coriander, Parsley, and Chives often bolt (go to seed) in the summer sun, but the post-Equinox light is exactly what they crave.
If your tunnel still feels a bit too warm during the midday peak, a light 50% UV Block shade cloth can be draped over the sunward side to keep your herbs from wilting while they establish. These fresh herbs will be a welcome addition to hearty autumn soups and stews.
Extend Your Season Beyond the Equinox
The beauty of a polytunnel is that the calendar no longer dictates your harvest. By sowing the right crops at the Equinox, you aren't just gardening for today—you are building a "pantry in the backyard" that will carry you through the coldest months of the year.
Need help choosing the right seeds or setup for your climate? Browse our full polytunnel range or contact our experts for advice on the best structure for your goals.
