Usually, the reasons for sunflowers dying are because of root rot due to overwatering and slow-draining soils or a lack of sun. Sunflowers need well-draining soil and 6-8 hours of sun. If the soil is consistently damp, the leaves turn yellow with a drooping, dying appearance. In too much shade, sunflowers wilt and die back.
The reason for indoor sunflowers dying because of a lack of sun or because their pot is too small.
Smaller pots hold less soil and therefore contain less nutrients and moisture. In small pots, the sunflower’s extensive roots cannot uptake the water and nutrients they need, which results in a drooping, dying appearance.
The reason for drooping, dying sunflower seedlings is often because the seedlings underdeveloped root system does not have access to enough moisture or because of high temperatures.
It is worth noting that most sunflower varieties are annuals, and therefore only live for one year before dying back.
Keep reading for how to implement the solutions to revive your dying sunflower (Helianthus annuus)…
Sunflower Drooping and Dying
- Symptoms. Leaves may droop and turn yellow or brown. Flower heads can also droop.
- Causes. Watering too often or slow-draining soils promotes the conditions for a fungal disease that causes drooping leaves that turn yellow. Not enough sun also causes wilting. Alkaline soils turn leaves yellow or brown. Sunflowers wilt due to cold weather and wilt die back each year.
Therefore the reason for a sunflower drooping and dying is more often because there is too much moisture around the roots rather then not enough.
Sunflowers prefer to grow in soil that is rich in organic matter which holds moisture yet drains effectively.
If the sunflower is watered too often or planted in heavy, boggy soils such as clay soil, then the roots cannot respire and therefore they cannot uptake the moisture and nutrients that the plant needs which results in drooping, yellowing leaves and flower heads.
Boggy conditions also promote fungal diseases such as root rot, mildew, and rust.
A lack of sunlight is also a common reason for a dying sunflower. In their native habitat sunflowers grow in open areas and grow tall so that they have a competitive advantage over other plants when it comes to sunlight.
8-10 hours of sunlight is considered optimal for sunflower growth and flowering. Whilst sunflowers can live in fewer hours of light, lower levels of light increases the risk of the sunflower drooping with lower leaves turning brown and dying.
It is also important to consider that whilst some sunflowers are perennial (come back every year) most sunflower varieties are annuals (die back after producing seeds) and only last one year before dying.
Cold weather is also a threat to sunflowers and they are more sensitive to cold than most ornamental plants in the garden. A sudden cold snap or frost can be the cause of a dying sunflower with brown leaves.
Typically the recommendation is to not plant out sunflowers if the soil temperature is below 60°F (16°C) (so the roots can establish) and it is important to wait until the threat of frost has passed and the weather has warmed up before planting out any sunflowers from seeds or plug plants.
Whilst sunflowers are tolerant of heat whilst established, wilting leaves and dying plants can be a problem if the sunflower does not have access to enough moisture when immature due to high temperatures and low rainfall, so it is important to water them generously twice a week in the first 60 days to promote healthy roots.
It should also be noted that sunflowers prefer slightly acidic soils of pH 6-6.8. Alkaline soil (which is soil higher than pH 7) can turn the leaves yellow or brown with stunted growth and drooping, dying appearance.
How to Revive a Sunflower Drooping and Dying
- Always plant sunflowers in well-draining soil composed of organic matter (compost). To avoid problems with slow-draining soils and overwatering amend the soil beforehand with compost to a depth of 12 inches. Compost retains moisture yet has a well-draining porous structure that allows excess water to drain away from the roots.
- If your sunflower is in boggy, heavy soil and wilting, then transplant it to a pot or raised bed. Sunflowers simply do not grow well in saturated heavy soils. Carefully fork out the sunflower and plant it in a large pot or raised bed. With pots, you can easily create the right soil conditions to suit the needs of the sunflower by planting it in multi-purpose compost that is preferably slightly acidic. With better drainage, the sunflower roots can breathe and the plant can recover.
- Transplant your sunflower to the sunniest area of your garden. A relatively open, south-facing location with as much sun as possible, emulates the sunny conditions of the sunflower’s native environment which helps to revive the wilting leaves and gives the sunflower enough energy to grow and display flowers.
- To avoid sunflowers wilting and dying due to drought water them generously twice a week if there has not been any significant rainfall, whilst they establish. It is important to give the sunflowers a generous soak, (rather than water too lightly) as this promotes good root growth and a more extensive root system helps the sunflower access more nutrients and greater stability in windy conditions. It is important that the soil is well-draining, yet moist in the first few weeks of growth.
- If the sunflower has fungal diseases such as mildew or rust on the lower leaves, the sunflower can still grow and display flowers. If certain leaves are particularly affected by powdery mildew then cut the leaves off with a sterile pair or pruners and dispose of the leaves by fire or into bin to prevent spreading fungal disease to other plants.
- If your soil is alkaline, grow sunflowers in pots. As sunflowers do not tolerate alkaline soils well, it is better to grow your sunflower in pots as it is far easier to create the optimal soil conditions in a pot than to change the pH of your garden soil.
If sunflowers have been damaged by cold snaps, then recovery is possible but whether or not they recover depends on the extent of the damage, with frosts usually causing sunflowers to die back.
If you live in a climate where frost is a threat in Spring, I recommend growing sunflowers indoors on a sunny window sill in compostable pots for 4 weeks as plug plants and then consulting a long-range weather forecast before planting them outdoors to give them the best chance of surviving in cool or unpredictable climates.
Once you have addressed the reasons for the wilting sunflower, move it to an area of full sun and ensure the soil is moist yet well-draining, the sunflower should make a recovery in the following weeks.
Indoor Potted Sunflowers Wilting and Dying
- Symptoms. Sunflowers with drooping leaves and flower heads, or not flowering at all whilst grown indoors.
- Causes. Most often the causes are not enough sunlight, small pots, or watering problems.
Most often the reason for indoor sunflowers dying is because they do not have enough light. Sunflowers can be grown indoors but they need at least 6 hours of sun per day. If the sunflower is in too much shade indoors then it does not flower and has a wilting, dying appearance.
To grow sunflowers indoors, it is imperative that they are on a south-facing window sill with at least 6 hours of light, (but ideally 8 hours of direct sunlight), or the sunflower does not have the energy to flower and they are likely to die back.
Watering is often an issue with indoor sunflowers as it can be very difficult to find the right balance of soil moisture due to different variables that can cause the sunflower to wilt such as:
- The size of the pot (small pots can dry out too quickly and the sunflower can exhaust the potting soil of nutrients).
- The fluctuations in temperatures due to indoor heating or air conditioning can dry out the soil and sap moisture from the leaves.
Both of these factors can increase the frequency with which an indoor sunflower needs watering.
Sometimes the sunflower’s potting soil can bake hard due to a combination of sunlight and indoor heat which can cause the soil to become hydrophobic which means that it repels water off the surface of the soil and down the side of the pot without actually infiltrating the soil and reaching the roots, which results in a drought-stressed, wilting, dying indoor sunflower.
However, it is important to note the potting soil should not be saturated, which can be an issue if you are watering too often or the pot does not have drainage holes in the base.
Even if the pot does have drainage holes, water can still pool around the base of the pot in any saucers, trays or decorative outer pots that are underneath the pot which can cause root rot and result in a dying sunflower.
How to Revive Wilting and Dying Potted Indoor Sunflowers
Simply move the sunflower to a window sill with more light if possible or plant the sunflower outdoors in a nice, sunny open area of the garden or front yard.
If you do not have a sunnier spot to move your sunflower, then some supplementary grow lights are a great way to ensure that the sunflower gets the light it needs to flower indoors, which are now available for reasonably affordable prices.
It is a good idea to check whether or not the sunflower’s roots are pot-bound. If so replant the sunflower in a pot one size up. If you replant the sunflower in a pot that is significantly larger than the previous pot, then it may take too long for the soil to dry which can cause root rot.
In a larger pot, the sunflower’s roots have more access to nutrients which should help to revive the sunflower.
To check whether soil moisture is an issue, feel the potting soil at the top of the pot to a finger depth and through the drainage hole at the base of the pot.
Ideally, sunflower potting soil should feel slightly moist.
If the soil feels too dry at the top and the base of the pot then submerge the root ball of the sunflower in a basin of water for 10 minutes or so. This ensures that water soaks into the soil properly if it has baked hard and reaches the roots.
After a good soak, take the sunflower out of the basin and allow the soil to drain. The leaves should perk up over the next few days.
If the potting soil feels boggy at the base and the pot scale back any watering and let the soil drain properly.
Replant the sunflower in a pot with drainage holes in the base and empty any trays or saucers of excess water regularly to ensure good drainage.
Once the soil drains properly the roots can respire and function properly so that they are able to transport water and nutrients to the sunflower leaves.
However, if the sunflower has been in boggy soil for too long then it is likely to have root rot and is very difficult for the plant to recover after its roots die back.
Sunflower Seedling Drooping
The reason a sunflower seedling is drooping is usually because of a combination of high temperatures and intense sunlight.
Both of these factors can dry the soil too quickly for the roots to draw up moisture.
Sunflower seedlings do not have a well-developed root system, so the leaves droop in response to excess heat as a survival strategy, to reduce the size of the leaf’s surface area which reduces water loss from the leaves due to transpiration.
This can often be the case if you are growing the seedlings indoors as the humidity is often much lower indoors, which can further sap moisture from the leaves and the soil.
When the sunflower is a seedling, the soil should be moist but not boggy, therefore I would caution against excess watering every day which can make the soil saturated as opposed to moist, which can deprive the roots of oxygen and cause the seedling to droop.
How to Save Drooping Sunflower Seedling…
To save the seedling, ensure the soil is evenly moist, but not boggy. This is achieved through good well-draining, porous compost, and more frequent watering whilst the seedling starts to grow.
It is important to be careful when watering seedlings, so you do not wash away the compost, so use a very fine shower head (rose) for your watering can.
Whilst the seedling is drooping, it is a good idea to temporarily move the seedling to a cooler area if possible, as say for example, a window sill can get very hot in Summer, whereas it may be cooler and more humid outdoors.
I recommend placing the seedlings in a location of morning sun (which is much cooler) followed by shade in the afternoon which reduces the temperatures and decreases the rate of evaporation from the soil and therefore reduces the stress on the plant.
- A dying sunflower is often because the sunflower is in too much shade or the soil is too damp. Sunflowers need at least 6 hours of sun and well-draining soil. Sunflowers droop and die back before flowering in too much shade. If the soil is too damp the sunflower’s leaves turn yellow with a wilting, dying appearance.
- The reason for potted sunflower leaves and flowers wilting and dying is because the pot is too small and dries out too quickly in full sun and the roots cannot draw up the moisture they need before the soil is dry, which causes the leaves to wilt.
- The reasons for indoor sunflowers dying are because of a lack of sunshine and their pots being too small. Sunflowers have extensive roots. Smaller pots have less capacity for soil and moisture so the sunflowers cannot uptake the water and nutrients they need, resulting in wilting, dying sunflowers.
- Sunflower seedlings wilt because of high temperatures which can dry out the soil. The seedling’s wilting leaves reduce the surface area of each leaf to help minimize water loss if the temperature is high and the soil is drying quickly.
- To revive dying sunflowers, it is important to emulate the conditions of their natural environment, by planting sunflowers in well-draining yet evenly moist soil, moving the sunflower to full sun, and always planting sunflowers in larger pots so their roots can uptake the nutrients and moisture it needs to grow and flower.