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

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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?
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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?
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19 Apr 22, (USA - Zone 5a climate)
Sandy soils just require more watering and fertilising.
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05 Apr 22, Stella Vance (USA - Zone 7a climate)
When is the best time to plant sunflowers or any flowers from seed?
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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.
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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?
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02 Aug 21, Renee (USA - Zone 6a climate)
Is it too late to plant sunflower seeds in Ohio (zone 6) and expect results?
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06 Aug 21, (USA - Zone 6a climate)
Go by the guide here.
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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?
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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
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One last thought -- and whether this is a good idea or not will depend on the "tastes" in your area. (using info from the net): The Jerusalem artichoke (Helianthus tuberosus) is closely related to sunflowers. Specialty producers treat Jerusalem artichokes as a very versatile, gourmet root vegetable under multiple names such as Sunchoke (created and trademarked by Frieda Caplan) and lambchoke, as well as sunroot, wild sunflower, earth apple, earth pear, and topinambour (in France and Germany). They have also been called French potatoes, German turnips, and Canadian artichokes or truffles. They can be sliced and eaten raw (after washing the edible skin) and are variously described as sweet, savory, nutty, and crunchy, similar to water chestnuts, jicama, or milder radishes. They are often boiled, roasted, or mashed, with a flavor very similar to potatoes or artichoke hearts. They can also be fermented or pickled, and ground into flour. Jerusalem artichokes look similar to ginger root or turmeric and potatoes. They can be short or long and brown, white, red, purple, or grey in skin color. Wild tubers are often red and plants are spread across fields; when cultivated, they appear white and clustered together. Tubers are oblong, with lumps or knobs. The inside is white until exposed to air when the flesh will begin to darken. More than 200 varieties of Jerusalem artichokes exist including Clearwater, Columbia, Mammoth, Oregon, Red Fuseau, Stampede, and White Fuseau. Jerusalem artichokes are a hardy perennial able to grow well in most soils. Ideally, the ground is loamy, loosely packed, and with a slightly alkaline pH value of around 7. Temperatures between 65 to 80°F (16c - 26 c) are preferred for optimal growth, along with 125 or more frost-free days. More sunlight is needed for the initial growing stages, then less is preferable as the tubers form. Precipitation will aid in growth, especially during sprouting, but too much moisture will waterlog plants. In commercial production, Jerusalem artichokes are raised annually, despite their perennial nature. Growth takes 7 months on average, seeds are often planted in early spring for best yields. ...................... certainly worth thinking about. Sunflowers for oil production probably have more "certainty" when it comes to demand. Sun chokes may not have the demand (initially - or maybe ever) in your area to support a farm dedicated to Sun chokes and Sun Chokes are know for their "delicate" skin which may make shipping tricky (avoiding spoilage)..

- Celeste Arcjer

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