Gardenia plants produce white creamy flowers and dark shining green leaves. When you see yellow gardenia leaves this means you are doing something wrong. In this article, I will answer why your gardenia leaves are turning yellow? What you can do to fix the yellow leaf problem?
There are many factors that directly affect the plant leaf color and texture. Low light, incorrect pH, and wrong watering techniques are the few commons reasons. All the yellow leaf causes are listed below with their best solutions.
Incorrect soil pH
The normal pH range for gardenia plants is betwen5.0 to 6.0. This means it prefers little acidic potting soil to grow. But we generally have alkaline soil and this creates the problem.
Too acidic or alkaline soil block the nutrient uptake system of the plant. This results in yellow gardenia leaves.
To bring down the soil pH you need to use acidifying soil amendments. Add them to the potting soil and make it suitable for your plants.
Within in few days, you will see the new growth of dark green leaves. Some of the half-yellow leaves again turn green. Whereas you need to remove the fully yellow gardenia leaves.
Both overwatering and underwatering trigger yellow leaves in gardenia plants. To avoid gardenia leaves turning yellow you need to learn the right watering technique.
General guidelines say give 1-inch water to your gardenia per week.
But this is not a full-proof formula. Therefore, my recommendation is to check the soil before watering it.
There are 2 methods to check the soil one is to insert your finger and feel the moisture. This technique is only successful if you have good experience in gardening.
The second and best method is to use soil testing meters. Read the moisture reading in the digital form.
Another benefit is
- you can use the same device to check the moisture of your outdoor garden soil.
- Your plants will never face dehydration problems.
Thirsty gardenia loses moisture from their leaves and this turns them yellow and brown. To keep them green and shining water your plants on right time. Always use fresh drinkable water for watering container plants.
Nutrient deficiencies are another common reason for yellow leaves in many plants. Lack of nitrogen and magnesium turns gardenia leaves yellow. To identify this issue, you need to check the fertility of the soil.
If you never fertilize your plant and it turns yellow after a year. Then this means the plant absorbs all the nutrients present in the potting soil. Now it needs more nutrients but the soil does not have them.
In this condition, you should use liquid fertilizer to boost plant health. Also, change the soil, and in new potting soil add some organic material. The benefit is organic material releases nutrients slowly. This makes a chain supply of nutrients to the plant roots.
Use Nitrogen-rich nutrients in case of gardenia leaves turning yellow.
Miracle-Gro and FoxFarm are the two manufacturers that make affordable plant nutrients. Use liquid form for gardenia plants.
Lack of sunlight
As we all know extra bright light can burn the leaves. But most of the growers do not know that the low light also causes problems.
6 to 8 hours of sunlight or bright light is necessary for better health.
If gardenia does not get proper light, they cannot complete the photosynthesis process. This means no more chlorophyll and no plant glucose. This results in gardenia leave turning yellow and brown.
To prevent this condition, use a plant light meter and measure the light lumens that your plant is receiving.
Hover the device over the plant and it will tell you the reading in digital form. Then according to the reading, you can adjust the plant location. I have my plant on my east-facing window sill. Grow lights are another option for dark areas. The light has to be a minimum of 200 watts to full fill its light needs.
Turn On the grow light for 10 hours per day.
There must be a draining hole at the bottom of the plant pot. This keeps the plants safe from accidental overwater. It also protects roots from many fungus diseases.
Secondly, the soil has to be well-draining soil. Never use garden soil in plant pots because doing so will surely block the nutrients to the plants. This results in yellow leaves.
Moreover, the garden soil becomes waterlogged when you water your plants. And houseplants like gardenias get infected by root rot in wet soggy soil.
This root fungus starts eating the root ball and green leaves turn yellow. For a healthy shining plant, your plant needs a healthy root system.
To identify this cause, check the potting soil if it is wet then take out the plant from its pot. Inspect the root ball and cut the damaged roots. Change the potting soil, wash the plant pot, and put it back in the same pot.
Note: Well-draining soil + Draining hole in the pot can save your plant from turning yellow. It also increases the draining power.
Pest & diseases
The last reason behind the gardenia yellow leaves is a pest infestation or a plant disease. The pests like aphids and spider mites suck the sap of the plant. They also make tiny holes in the plant leaves. This makes the leaves dehydrated and they turn yellow.
To avoid pest infestations, keep the growing room neat and clean. Use neem oil spray twice a month on your plants.
In case your see pests on your plant leaves. Buy an insecticidal soap for plants and wash your infected plant. This will kill all pests in minutes. The second option is wiping each leaf with rubbing alcohol. This is not possible in the case of gardenia because it produces many leaves. Wiping them manually is not possible.
Fungal diseases are another common reason. Use fungicides that contain copper to combat leaf fungal and stem fungal problems.
Do not use neem oil after using fungicides. It is a preventive method, it cannot cure the disease.
Now you know all the possible causes that make green leaves yellow. As you can see some causes are easy to fix whereas others take time to resolve.
Light and soil pH is easy to deal with. The real challenge comes with fungicide problems. They took time to heal.
It is best to prevent these problems. For more information on plants check our houseplant section.