Growing Sunflower

helianthus annuus : Asteraceae / the daisy family

Jan F M A M J J A S O N Dec
    S S S S S          
      T T T T T T      
      P P P P P        

(Best months for growing Sunflower in Australia - tropical regions)

  • S = Plant undercover in seed trays
  • T = Plant out (transplant) seedlings
  • P = Sow seed
  • Sow in garden. Sow seed at a depth approximately three times the diameter of the seed. Best planted at soil temperatures between 50°F and 86°F. (Show °C/cm)
  • Space plants: 8 - 18 inches apart
  • Harvest in 10-11 weeks.
  • Compatible with (can grow beside): Cucumbers, Melons, Sweetcorn, Squash
  • Avoid growing close to: Potatoes

Your comments and tips

24 May 14, Anton Marais (Australia - arid climate)
Is the Margeret River area good for the arid type sunflower - I'm from - South Africa where we used to travel down to the coast thro sunflower fields up to 300 to 400 km long - I love them on the other side of the road was gaint corn called a mielies in sa
10 May 14, dan (Australia - sub-tropical climate)
I'm planning for wedding on october 11. I'd love to have a big patch of flowering sunflowers. It's in Lennox Head (near Byron) When would be a good time to plant?
16 Aug 14, Pete (Australia - sub-tropical climate)
Hi Dan, I'm only going from the 10-12 weeks to harvest in the description, but if you want them for the end of September, you better get them in the ground ASAP! Unless you buy seedlings, in which case they could be anywhere from 2-4 weeks old.
21 Jul 13, Peter Smith (Australia - temperate climate)
The cheapest place I've found to get sunflower seeds is in the birdseed section of the supermarket. The ones I bought came up well. There were two varieties; ones with a single large flower and ones with multiple smaller flowers. One bag gave enough seeds for me and to supply every gardener I know.
22 Jul 13, (Australia - temperate climate)
Yes - those seeds grow really well!
11 Jul 13, Rule the world (Australia - cool/mountain climate)
Sunflowers, Grow for your chooks. They love them!
11 Apr 13, carine ferreira (Australia - sub-tropical climate)
planted sunflowers in pots 10 april want flowers to be at their peak 23 june. Think we ll be ok?
31 Jan 13, Pam (New Zealand - sub-tropical climate)
I transplanted 150 Sunflower seedlings and now have lovely big strong plants and lots of flowers out. Hasnt affected mine any.
12 Aug 11, Tony (Australia - sub-tropical climate)
I transplanted 4 sunflowers from seedling pots and they grew very well. They were about 10cm tall when I did this.
01 Dec 10, Patrick Conteh (Australia - temperate climate)
Please advise on the variety of sunflower to grow commercially for oil in Sierra Leone with temperatures that average 25 degrees C, Rainfall not a problem
Showing 31 - 40 of 78 comments

Most seeds have what is know as a "germination" temperature -- this ensures that seeds do not germinate in the middle of winter. Here are some basic germination temperatures in F ==> Snapdragon (Antirrhinum majus) 70 Wax Begonia (Begonia x semperflorens-cultorum) 70-75 , Annual Aster (Callistephus chinensis) 70 , Vinca (Cathranthus roseus) 70-75 , Cockscomb (Cleosia spp.) 70-75 , Bachelor's Button (Centaurea cyanus) 65-70 , Cosmos (Cosmos spp.) 70 , Lisianthus (Eustoma grandiflorum) 75 , Globe Amaranth (Gomphrena globosa) 70 , Sunflower* (Helianthus annuus) 70 , Strawflower (Helichrysum bracteatum) 70-75 . Furthermore the germination temperature needs to be sustained -- so for example if the temperature hit 70f for a couple of hours in the middle of the day and the reset of the time the temperature is 40f ==> germination will probably not occur. Sustained temperatures is how the seed KNOWS it is spring/summer -- when you start your seeds indoors, you are tricking the plant into thinking it is spring and the temps are good and it is a good time to germinate (the seedling will not freeze to death). The average flower temps are around 70f for germination. Herbs tend to require much higher germination temps and that is why many people have difficulty growing them from seed -- Rosemary being one of the worst: Rosemary (Rosmarinus officinalis) 80-90 °F (27-32 °C). If you plant your seeds before OPTIMAL germination temperatures are present, you do risk rotting the seed if the ground is very wet... but for the most part, the seed will just lay dormant until all of its germination conditions are met- then it will germinate.

- Celeste Archer

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This planting guide is a general reference intended for home gardeners. We recommend that you take into account your local conditions in making planting decisions. Gardenate is not a farming or commercial advisory service. For specific advice, please contact your local plant suppliers, gardening groups, or agricultural department. The information on this site is presented in good faith, but we take no responsibility as to the accuracy of the information provided.
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