Whether you garden in the ground, in raised beds, or on the patio, sunflowers are a great addition or re-addition to your plant family. Read on for simple, straightforward specifics about growing sunflowers.
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Family | Container Size | Good Companions | Bad Companions | Soil Conditions | Germination | Sun | Water | Temperature Range | Height | Lifespan | Reproduction | Yield Per Plant | Ingestibility | Further Reading
What Family Do Sunflowers Belong To?
Sunflowers (Helianthus spp.) belong to the Asteraceae family, also known as the daisy family.
Some of their relatives include chamomile, lettuce, and artichoke.
What Size Container Should I Use for Growing Sunflowers?
The minimum container depth recommended for sunflowers is 12 inches.
Learn more in our Choosing the Right Planter for Your Container Garden article here.
What Are Good Companion Plants for Sunflowers?
Some of sunflowers' best companions are as follows:
- Peppers like bell pepper and jalapeño
- Corn, which increases sunflowers' yield
- Cucumber
- Squash
- Melons
- Tomato
- Fennel
- Bush beans
- Clematis
- Coreopsis
- Dahlia
- Artichoke
- Daylily
- Nettle
- Motherwort
- Echinacea
- Iris
- Lemon balm
- Mints like peppermint and spearmint
- Rose
- Blackberry
- Thyme
What Are Bad Companion Plants for Sunflowers?
Sunflowers are not compatible with every plant. Some things to avoid planting with sunflowers are as follows:
What Soil Conditions Do Sunflowers Need?
Sunflowers prefer loose, well-draining soil with a pH of 6.0 to 7.5.
How Long Do Sunflowers Take to Germinate?
Sunflowers take 10-14 days to germinate at a temperature of 50-85°F.
Within this range, germination will be fastest if the temperature is 70°F or above.
How Much Sun Do Sunflowers Need?
You guessed it! Sunflowers need full sun, meaning 6 hours or more of sun per day, even in hot regions that normally need extra shade.
Sunflower leaves and stalks can grow in dappled shade and part shade. But they will do so slowly, making them more susceptible to pests and disease. The plant is unlikely to flower in the shade.
How Much Water Do Sunflowers Need?
Sunflowers need 1 inch of water per week.
An even more reliable indicator of watering needs is the soil moisture level. When the top 2 inches of soil are dry, give the sunflowers and their long taproots a deep, thorough watering.
What Is the Ideal Temperature Range for Growing Sunflowers?
Sunflowers grow fastest in temperatures of 70-80°F.
This is their ideal temperature range. Although they will grow in temperatures both cooler and warmer than this range, the growth could be slower or even stunted.
Most sunflowers can tolerate extreme heat, including temperatures well in excess of 100°F, making them an excellent choice for hot regions.
Many sunflower varieties are also very hardy, withstanding temperatures down to 25°F.
Minimum and maximum temperatures will vary by variety. Some sunflower varieties are bred for earlier maturity and others for hotter climates.
How Tall Do Sunflowers Get?
The average height of most common sunflower varieties is 6-10 feet.
Giant and mammoth varieties can reach heights of 15-20 feet.
Are Sunflowers Annual, Biennial, or Perennial?
Interestingly, both annual and perennial sunflowers are readily available and commonly grown.
Some varieties, such as Helianthus annus, are annual. This means that they start and end their lives in the same year.
Other varieties -- such as Helianthus angustifolius, Helianthus debilis, and Helianthus maximiliani -- are perennial, meaning that they live for longer than a couple years.
How Do Sunflowers Reproduce?
Sunflowers reproduce by seed.
How Many Sunflowers and Sunflower Seeds Are Produced Per Plant?
For sunflowers, how many seeds are produced per plant (also called the yield) largely depends on the variety.
Most sunflowers yield 1 to 2.5 pounds of seeds per plant.
Each sunflower plant produces 1 large head.
Can Sunflowers Be Ingested?
Sunflower seeds, flowerheads, petals, leaves, and stalks (in other words, all above-ground parts) are edible.
Sunflower roots are also technically edible. But since they are long, skinny taproots, they usually do not make a practical meal. Other relatives like Jerusalem artichoke and elecampane have thicker roots that make more substantial meals.
Sunflower leaves and petals have anti-inflammatory, expectorant, and astringent properties and can be used in herbal preparations. The most common preparation is tea.
Sunflower seeds also have expectorant properties, both when decocted and when eaten.
There are no known safety concerns associated with ingesting sunflowers.
Further Reading
This article is intended as a quick-reference guide for gardeners. Consult your seed packet or seed catalog for variety-specific information.
When you have a bumper crop of sunflowers rolling in, you may not have enough time for long, complicated recipes or many-step preservation procedures. Check out my article on quick, simple uses for sunflowers here!
Sunflowers are featured in these Plant to Plate articles: