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Sunflowers (Helianthus annuus) Care Guide

Sunflowers (Helianthus annuus) are popular with many gardeners due to their cheerful look and when grown en masse, provide a spectacular backdrop for any garden, big or small. The seeds are huge which makes them easy to handle.

Being annuals, sunflowers grow quickly as well, so they are perfect for beginners and children who are keen to see fast results.

Sunflowers come in a huge range of varieties and while most of us are familiar with yellow sunflowers, did you know that they also come in red, orange and white varieties?

Not only that, different varieties of sunflowers grow to different heights. Dwarf varieties (eg. ‘Teddy Bear’) grow up to 50 cm tall while there are varieties that reach 3 m heights (‘Russian Giant’)!

Common Problems

  1. Planting out too early – The young seedlings are susceptible to snail and slug damage. To prevent this, use snail pellets.
  2. Sudden wilting – This could be caused by white mould or Sclerotinia stem rot. Ensure that re your soil is well-drained and avoid watering past mid day, so that the plants and soil surface will be dry before sunset.

Common Mistakes

  1. Harvesting seeds too early – Never cut the flower head too early or when the petals are still on the flowers. Wait till the petals have fallen off. When the calyx turns yellowish brown, the sunflower seeds are mature and ready to be harvested.
  2. Staking sunflowers – While staking is well-intentioned to prevent the plant from toppling, this is not necessary for sunflowers. Plant sunflowers in well-draining soil, so that the roots will be able to grow deeply, providing good support for the stem and entire plant.

Care Requirements & Guide

Watering: Deep watering will encourage the roots to grow deeply which ensures the stability of the plant, thus avoiding the need to stake them.

Light: Sunflowers thrive in full sun but need to be protected from strong winds.

Temperature: Sunflowers are annuals which grow in summer. Attempting to grow them in other seasons will be met with dismal failure.

Soil: Sunflowers are not fussy and grow in all sorts of soil conditions, provided they are well drained.

Fertiliser: Too much fertiliser may result in leggy growth, although a good slow-acting fertiliser may result in larger flowers.

Propagation: Sunflowers are best propagated by seed. Plant the seeds about 15 cm apart. Cover the seeds and water the soil regularly to ensure that it is moist. The first leaves should in 7 to 10 days. Generally sunflower plants do not transplant well, so if they are grown in a pot, they are best transplated as seedlings. For best results, plant them where they are meant to grow.

Fun Fact about Sunflowers

Sunflowers have the ability to turn themselves to face the sun. In fact, the French word for sunflower is tournesol, which means just that – “turned sun”!

Which Sunflower Seeds Should I Grow?

We recommend the following:

Garden-in-a-Pail (Sunflower) includes a steel pail (5.5″ high x 6″ diameter), seeds, growing medium, coconut husks for drainage and step-by-step directions. This beloved dwarf variety has 12-15 inches tall (30–38cm) stalks with flowers that can reach 5 inches (12.7cm) across, heart-shaped leaves and edible seeds.
Mini Sunflower Garden in a Bag includes a bag (10″ high x 6.5″ wide), seeds, growing medium, coconut husks for drainage and step-by-step directions. This is a french dwarf variety.
Sunflower Van Gogh Scatter Garden is a collection of a beautiful mix of the colors and textures represented in paintings by this master. It includes 5 sunflower seed varieties, growing directions and a grow bag (7.25″ high x 3.5″ wide)

Alternatively, you could consider other seed packs available from time to time. Happy planting!