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When to Plant Sunflower Seeds in Australia

The ideal time to sow your sunflower seeds will depend on where you are in Australia. Ideally, the soil temperature should be between 10 to 30 degrees Celsius.

Sunflowers are a delight to grow in the garden. The bright happy blooms always put a smile on my face as they face the sun. Actually, that’s why they’re called sunflowers because the flowers always seem to face the sun.

If you want to plant these beauties in your garden, you’ll want to know the best time to sow the seeds so that you’ll have optimum success and end up with lots of bright blooms.

sunflowers | Plant care

When is the best time to plant sunflower seeds in the garden?

The ideal time to sow your sunflower seeds will depend on where you are in Australia. Ideally, the soil temperature should be between 10 to 30 degrees Celsius to allow for optimum germination.

For temperate regions such as Melbourne and Perth, this would be around October to November. However, if you want to start your seeds in seedling trays, you can put these in as early as September and plant the seedlings into the garden from October.

sunflower seedlings | Plant care

Warmer regions such as Sydney have a much longer sowing window. Sydney gardeners can sow sunflower seeds in the garden from August right through until March the following year. 

In this climatic region, you can even start your seeds in seedling trays as early as July but hold off planting them in the garden until September. 

Those gardeners who experience cooler weather such as on the tablelands of NSW, Canberra and Tasmania, can also sow sunflower seeds in the garden from October to November and start seeds in trays in September.

In tropical regions north of Rockhampton in Queensland and north of Carnarvon in Western Australia, sunflower seeds can be sown in the garden from April through to August and seeds can be started in trays in March.

How to plant sunflower seeds in your garden

Sowing sunflower seeds is as easy as it gets. Choose a sunny location and enrich the soil with plenty of compost or other organic matter. 

Sunflowers are happiest when they receive at least 6 to 8 hours of sunlight daily. 

They’ll also grow in most soil types as long as the soil is free-draining and has been enriched with some organic matter.

Sow the seeds around 60 cm apart and at a depth of 2cm. Water the soil well.

sunflower seeds | Plant care

How to care for sunflowers

Sunflowers do need to be kept watered to ensure they develop a good root system and healthy blooms. 

Try to water your sunflowers in the morning so that they’re not in wet soil overnight. This avoids the possibility of root rot developing.

sunflower watering | Plant care

Once your sunflowers start to produce their tall flower stems, they will need to be staked to protect them from strong winds. The flower heads are quite heavy, especially when they start to produce seeds, so they need a little extra support to stop them from falling over from the weight.

It’s also a good idea to spread a layer of mulch around the base of the plants once the young seedlings start to grow. This will help to keep the soil moist and prevent weeds from growing.

You might also find that snails and slugs will be tempted by the young sunflower seedlings. You can control these either by laying out baits or using Multiguard snail and slug pellets.

To help your sunflowers grow nice and tall, consider giving them a liquid feed every 2 to 3 weeks during their growing season.

FAQ

Do sunflowers grow all year round in Australia?

In some parts of the country, primarily sub-tropical areas and arid regions, sunflowers will tend to grow all year round. However, in cooler regions, they won’t survive the frost. Plus, the high humidity during summer in tropical regions is also not ideal.

How long do sunflowers take to grow?

If you’re growing sunflowers from seed, it will usually take around 8 to 10 weeks before you’ll get flowers. They should reach their full height in around 12 weeks.

Do sunflowers pop up every year?

Sunflowers are annuals and need to be grown from seed every year because they complete their entire lifecycle in one season. However, if you leave the heads on your sunflowers so that they can produce seeds, some of these seeds may germinate the following year if they’ve dropped to the ground.

Where do sunflowers grow best in Australia?

Sunflowers can be grown in most parts of the country but they grow best in arid, temperate and sub-tropical regions of the country.

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Annette Hird

Annette Hird is a gardening expert with many years of experience in a range of gardening related positions. She has an Associate Diploma of Applied Science in Horticulture and has worked in a variety of production nurseries, primarily as a propagator. She has also been responsible for a large homestead garden that included lawn care, fruit trees, roses and many other ornamental plants. More recently, Annette has concentrated on improving the garden landscape of the homes that she has lived in and focused a lot of energy on growing edible plants as well. She now enjoys sharing her experience and knowledge with others by writing articles about all facets of gardening and growing plants.

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