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 7a 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

Your comments and tips

07 Apr 21, Donna Mourra (USA - Zone 10b climate)
I'm looking for a sunflower plant for Zone 10
08 Apr 21, Anonymous (USA - Zone 10b climate)
Google a sunflower seed selling website and pick one out.
06 Jul 21, Tracey (USA - Zone 9b climate)
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?
07 Jul 21, Liz (New Zealand - temperate climate)
If they survive the move and don't have too much root damage, then water every two to three days. to keep the roots damp but not swamped.
10 Jul 21, Anon (USA - Zone 11b climate)
The longer you leave to transplant something the harder it is to have it survive. The roots can not take up enough water to keep a full grown plant a live. In zone 9b you should have harvested the sunflower by now. You transplant when plants are young 2-6 new leaf stage
02 Aug 21, Renee (USA - Zone 6a climate)
Is it too late to plant sunflower seeds in Ohio (zone 6) and expect results?
06 Aug 21, (USA - Zone 6a climate)
Go by the guide here.
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?
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.
Showing 11 - 20 of 35 comments

If they survive the move and don't have too much root damage, then water every two to three days. to keep the roots damp but not swamped.

- Liz

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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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