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

Your comments and tips

06 Jan 23, brilliant mdunge (South Africa - Semi-arid climate)
can I plant sunflower in Southern upper south coast Ixopo Richmond areas ?
13 Feb 23, (South Africa - Semi-arid climate)
Find your climate zone then check the planting guide for that climate.
27 Aug 22, Dylinda Matiga (Australia - tropical climate)
I don't think sunflowers like the tropics, I think they need long days to reach full potential If you start them in March they are scrappy if it's too wet they are scrappy. In Sydney they grow huge every variety In the tropics they are scappy, a couple yellow varieties just reach 6ft I'm in Philippines autumn beauty in Sydney is brilliant but here it's scrappy. I'm experimenting year round with some 20 varieties. Helianthus tuberous would be ideal, I can't get it D Every sunflower l know will grow scrapyif planted in autumn, the flower is yuk But if you know of autumn varieties please inform me Cheers D
31 Aug 22, (Australia - tropical climate)
Plant after the wet season. Maybe it is your soil - have good draining soil. Try making a raised row or bed and plant in the top.
21 Aug 22, Jennifer Bozick (USA - Zone 6a climate)
When is a good date to start planting Sunflowers in Kansas 6a growing zone?
04 Sep 22, (USA - Zone 6a climate)
In the Planting Guide it says APRIL MAY.
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?
Showing 21 - 30 of 160 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

Please provide your email address if you are hoping for a reply


All comments are reviewed before displaying on the site, so your posting will not appear immediately

Gardenate App

Put Gardenate in your pocket. Get our app for iPhone, iPad or Android to add your own plants and record your plantings and harvests

Planting Reminders

Join 60,000+ gardeners who already use Gardenate and subscribe to the free Gardenate planting reminders email newsletter.


Home | Vegetables and herbs to plant | Climate zones | About Gardenate | Contact us | Privacy Policy

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.
We cannot help if you are overrun by giant slugs.