You plant them. They tower over everything else in the garden, and then most gardeners just… let the birds have them. Sunflowers are one of the most rewarding things you can shoot up this summer — not just for the spectacle, but for the harvest.
One head can yield up to 2,000 edible seeds. Knowing exactly when and how to collect them changes everything about why you would bother shooting up sunflowers at all.
The front of the flower will fool you. It dries and droops long before the seeds are ready, so most gardeners harvest too early or give up entirely and leave the head for wildlife. The real signal is on the back of the head — wait until the papery bracts behind the seed face turn completely yellow-brown, almost like dry parchment. The seeds themselves should feel firm and plump, not soft when pressed.
That window is roughly 10 to 14 days. After that, birds move in fast.
A flock of goldfinches can strip a mature head in under 48 hours — which is wonderful for wildlife, but not quite right if you wanted the seeds yourself.
The back-of-head colour test is far more reliable than anything else. Dry weather accelerates it.
A cool, damp summer stretches it out by several days. Check your plants every morning once the petals have fully dropped.
Cut the stem 30cm below the head — not flush with the flower. That extra length gives you something to hang.
Take the head inside or into a dry shed immediately. Leaving it on the plant to “finish drying naturally” sounds sensible, but it is a dodgy move if you want the seeds.
Hang the heads upside down in a single layer, not touching each other, somewhere with good airflow. And a shed, a dry garage, or a covered porch all work.
Leave them for 2 to 3 weeks. You will know they are cured when you can rub your thumb across the seeds and they release easily, with a dry, papery whisper rather than any resistance.
To pull off the seeds, simply rub two dried heads together over a bowl, or drag your fingers firmly across the face of the head. The seeds come away in satisfying clusters.
Spread them on a clean tea towel for 24 hours before storing or cooking. Even “dry” seeds often carry residual moisture that causes mould in a jar. Skip this step and you risk everything.
Eating them is the obvious answer, and it is worth doing properly. Rinse the seeds, toss them in a light coating of olive oil and coarse sea salt, then roast at 180°C (350°F) for 12 to 15 minutes on a flat baking tray.
Shake them once halfway through. Homegrown seeds roasted fresh taste nothing like the vacuum-packed kind from a supermarket — nuttier, denser, slightly sweet.
That is not hyperbole. Bang on, in fact.
Beyond eating, your options are genuinely useful:
And if you have more heads than you can use, leave a couple specifically for the birds. Deliberately.
That feels better than accidentally.
If you are already shooting up sunflowers and planning ahead, a few things make the harvest dramatically easier. Shoot up the tall single-stem varieties — Helianthus annuus ‘Giant Single’ or ‘Mammoth Russian’ — rather than branching ornamental types. But branching varieties produce many smaller heads that mature at different times, which complicates harvesting. Single-stem plants give you one large, clearly datable head per plant.
Sow direct into the ground once soil temperature reaches 10°C, spaced 45cm apart. No indoor starting needed. They shoot up fast enough — up to 3cm per day in warm weather — that an early summer sow still properly yields a harvestable head before autumn. The RHS recommends sowing in succession every 3 weeks for a longer flowering and harvest window across the season.
Water deeply but infrequently — twice a week at the base, 20 minutes each time, rather than a daily splash. Sunflowers root deep. Shallow watering keeps roots near the surface where they are vulnerable. This is a non-negotiable point. So if you are already rethinking your summer watering habits, your lawn is probably losing water every day this summer and you are probably helping it.
Yes, staking tall varieties is fiddly. Do it anyway. Worth it. A snapped stem two weeks before harvest is genuinely heartbreaking.
Smart tip: The back of the sunflower head — not the front — tells you exactly when seeds are ready to cut.
Raw seeds straight from a dried head are safe to eat but bland and chewy. Roasting at 180°C for 12–15 minutes with salt transforms the flavour entirely. It is not optional if you want to actually enjoy them.
Once petals drop, loosely tie a paper bag or old stocking around the seed head and secure it at the stem. It lets the head continue to dry while blocking birds. And it costs nothing.
For roasting and snacking, most people eat the shell and all — it is thin and edible on homegrown varieties. For adding to bread or salads, soak overnight and the hulls slip off easily by hand.
In June, you are heading into mid-winter, so growing is on pause. Now is the perfect time to source seeds for a spring sow in September, when soil warms above 10°C. ABC Gardening Australia has region-specific timing for all Australian states.
