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 10°C and 30°C. (Show °F/in)
  • Space plants: 20 - 45 cm 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

13 Aug 22, Theresa C. Dougherty (USA - Zone 7b climate)
Can I plant sunflower seeds in mid August to get fall sunflowers .? I live in zone 7 b ,I grow them first in side and plant outside .
27 Jun 22, Ruby (Canada - Zone 3b Temperate Warm Summer climate)
What about growing media
29 Jun 22, marco (Australia - arid climate)
hi i live on the gold coast Queensland .i planted sunflower from seed around six weeks ago .flowers are popping out now .i live in sub tropical area . plant in a pot first ,let it grow strong then transplant . they are fun to have in the garden .
23 Jun 22, Cristal Chacon (USA - Zone 8b climate)
I planted sunflower seeds today. Hoping to get blooms by mid August. Do you think this will happen? Or not enough time?
27 May 22, Harris, Joseph (Canada - Zone 6a Temperate Warm Summer climate)
Where can I buy perennial sunflowers in Quebec or Ontario (preferably Loddon Gold) My internet search, for now, has been unsuccessful - any help will be most appreciated.
14 Apr 22, Marjorie (USA - Zone 9b climate)
I’m planting mammoth sunflower in zone 9b (FL). I started the seeds in containers and moved them to the ground. For some flowers, I dug holes and filled with garden soil. For others, I planted in the ground, which is sandy. Those seem to be doing okay, too. They get sun from sunrise to sundown. Would you plant them in sandy soil?
19 Apr 22, (USA - Zone 5a climate)
Sandy soils just require more watering and fertilising.
05 Apr 22, Stella Vance (USA - Zone 7a climate)
When is the best time to plant sunflowers or any flowers from seed?
10 Apr 22, Celeste Archer (Canada - Zone 7b Mild Temperate climate)
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.
24 Mar 22, Pete (USA - Zone 8b climate)
What ph is required for sunflowers. Im guessing 7.0. Do they benefit from composted chicken droppings?
Showing 1 - 10 of 133 comments

I’m new at this and just picked a 6ft sunflower roots and all in Texas and I’m going to replant in Arizona Zone9B. How often do they have to be watered?

- Tracey

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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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