Growing Sunflower

helianthus annuus : Asteraceae / the daisy family

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

(Best months for growing Sunflower in USA - Zone 5a regions)

  • 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
  • Sunflowers
  • Young plants

Sunflowers need full sun and grow best in fertile, well-drained, moist soil with plenty of mulch. Sunflowers do not like to be transplanted so are best grown direct from seed. The giant or Russian varieties are preferred for seed production.

Grow to 1 - 2 metres (4 - 6 ft) so need staking or protection from the wind. Protect seed heads from birds when ripening with nets or paper bags. Chickens love a sunflower head hung for them to peck!

Culinary hints - cooking and eating Sunflower

Use seeds fresh or toasted or press for oil.

Your comments and tips

05 Dec 23, nancy aldape (USA - Zone 9a climate)
I love sunflowers
10 Oct 23, Kathleen (USA - Zone 4a climate)
Not sure if Im in zone 4a or 4b (Ossipee, NH). When should I plant sunflower seeds?
12 Sep 23, Anonymous (USA - Zone 7a climate)
I live in Northern California mountains. Zone 7a. Can I allow mammoth sunflower seeds to drop in fall to winterize before spring?
14 Sep 23, Anonymous (USA - Zone 8b climate)
Maybe you would pick them and store them.
26 Aug 23, Linda (Canada - Zone 3a Temperate Short Summer climate)
I would like to know what sunflower seeds can I plant in September in calgary zone 3
06 Sep 23, Anonymous (Canada - Zone 6a Temperate Warm Summer climate)
Any variety.
20 May 23, David (USA - Zone 4b climate)
Am in zone 4b. Is there a Sunflower I can plant that only gets 2 feet tall?
06 Jul 23, Brayden (USA - Zone 8b climate)
Botanical Interests has some good dwarf varieties like Sunspot Dwarf that grows 18-24" tall and is good for container planting
12 Apr 23, Chris Harcoan (Australia - temperate climate)
When is the best time to plant sunflowers in Mildura Victoria...
03 Apr 23, Helene Snyders (South Africa - Summer rainfall climate)
Where can I get seed of Sunflower Single Sunspot Helianthus annuus regards Helene Snyders
Showing 1 - 10 of 156 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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