Yes, sunflowers can grow in the shade but won’t flourish.
Planting sunflowers in the shade will result in little flowers, and seeds won’t grow well.
As their name (sun) suggests, sunflowers require abundant sun to grow properly.
The plant is native to Central America and prospers in warm, sunny conditions.
That’s why it’s recommended to plant sunflowers in late spring when they will get at least 6 hours of sunlight.
Sunflowers can grow in shade areas, but don’t expect a bountiful harvest if you do that.
For the best results, a sunflower needs 6 to 8 hours of sunlight.
Therefore, you should plant sunflowers in an open area where they receive abundant sunlight from morning to evening.
What Happens When You Plant Sunflowers in Shade?
Sunflowers have heliotropic qualities.
This means that they follow the path of the sun. However, this applies only to the sunflower’s buds.
They face the east when the sun rises and follow the sun to the west as it sets.
After the plant blooms and the stem hardens, the flowers face the east and no longer move with the sun.
So, if the plant is not receiving enough sunlight because of shade, it will not bloom well.
As a result, it will lead to stunted growth.
The plant will be weak and unhealthy.
Low Seed Production
If sunflower is grown within the right conditions, it should produce at least 1, 000 seeds.
These seeds are edible and are used for a variety of purposes around the world.
But if the conditions are not suitable, such as low light or shade, expect a bad harvest.
You will harvest fewer seeds than a person who grows the plant in full sunlight.
Risk of Fungal Infection
Sunflowers are vigorous plants that can defy harsh conditions and flourish.
They can grow in different soils as long as they receive enough nutrients and water.
They can also grow in shade areas, but you risk losing your plant or having a lower production.
One of the disadvantages of planting sunflowers under shade is exposing them to diseases.
A fungal disease such as Phoma blight thrives in wet conditions.
Therefore, if your plant is not getting enough sunlight, it may be attacked by this fungal disease.
Phoma blight attacks the plant when it starts flowering.
You may notice black lesions on the stem.
Also, you may see dark-colored, poorly shaped lesions show up on leaves and flowers.
This fungal infection may cause your plant to die or produce little seeds.
Apart from Phoma blight, other diseases that might attack your plant in shade areas are powdery mildew and white mold.
With enough sunlight, none of these diseases will survive.
The sunflower will dry out dew that gathers at night and attract the parasites that cause these diseases.
Sunflowers are known as one of the best pollinators.
These plants feature tall and brightly colored flowers that attract insect pollinators from a distance.
Because of their outstanding visibility, bees, moths, wasps, beetles, and butterflies fly from far to land on the plant.
What attracts these pollinators is the colorful petals of the sunflower and the warmth of the daily sunlight.
Thus, if you plant the sunflower in a shaded area, the pollinators won’t detect or get attracted to the plant easily.
This will hinder pollination to some extent.
In the end, they will affect the production of seeds, which is the primary purpose of sunflowers.
Will They Thrive in Partial Shade?
Sunflowers need full sun to grow and bloom, but they can also be cultivated in partial shade with the right conditions.
If you don’t have many options on where to plant your sunflowers, you must pick a spot with at least four hours of direct sun each day.
However, you need at least six hours for optimal growth.
Select dwarf varieties that are more suitable for partial shade.
These include ‘Autumn Beauty,’ ‘Teddy Bear,’ and ‘Mauve Mist,’ which are smaller than traditional sunflowers but still produce beautiful blooms.
At the same time, to increase the chances of success, add organic matter like compost or fish emulsion to the soil and water the plants more often than those grown in full sun.
Fertilize with organic fertilizer regularly, as sunflowers need plenty of nutrition.
Consider staking tall varieties, as they are more top-heavy than those grown in full sun.
With the proper care and attention, sunflowers can still produce an impressive harvest of flowers and seeds, even in partial shade.
What Else Do Sunflowers Need Apart From Sunlight?
Sunflower is a hardcore plant that can survive in harsh weather.
However, it would help if you planted it in favorable conditions before it attained the hardcore level.
Young sunflowers are weak and need proper conditions to grow.
The best time to plant sunflowers is after the danger of frost has passed.
Additionally, the soil temperature should be 70 degrees to 75 degrees F.
On top of that, you should sow the seeds when the soil temperature is 55 degrees F or warmer.
Sunflowers may be drought and heat tolerant, but they need frequent watering to flourish.
Sunflower needs even more water in the early stages of growth.
It would help if you watered the seeds daily to keep the soil moist for proper development.
A young sunflower should be watered after every few days, more so if the soil is hot and dry.
When the plants strengthen, and the flower becomes established, water only once a week.
Do not water the leaves or flowers, but at the base of the plant.
This will discourage disease build-up.
As stated earlier, sunflowers can thrive in various types of soils.
They don’t need a lot of nutrients to survive.
But if your soil is not nutrient-rich, you can add some fertilizer.
If you have compost, it will be the best solution.
Add it on top of the soil.
But if you don’t compost, acquire slow-release fertilizer and apply it similarly.
Avoid adding fertilizer close to the plant, as excess nitrogen may delay flowering.
Control Pests and Diseases
Like any other plant, sunflowers will also attract pests and diseases.
Snails, slugs, squirrels, birds, and deer will want to feed on your plant.
Apply repellents for slugs and snails, create a fence for squirrels and deer, and keep your plant moist to prevent diseases.
Whether you plant a sunflower for its beauty or as a food source, you must ensure that the conditions are right.
Sunflowers can grow in the shade but won’t grow to their full potential.
Growing sunflowers in the shade expose them to many diseases and pests.
Sunflower needs at least 6 hours of full sunlight to grow to their full potential.
Also, with enough light, the plant will fight off fungal infections and different diseases.
It will also attract pollinators, which is crucial for the multiplication of sunflowers.
Therefore, plant your sunflower where it gets 6 to 8 hours of sunlight and not in a shaded area.
Even if you’re growing sunflowers indoors, place them close to a south-facing window where it gets enough light.
Apart from sunlight, ensure that the plant receives the right fertilizer, water, and proper care.