Parley is one of the fun herbs to grow as a potted plant in your herb garden. But it can be finicky sometimes and you will see some yellowing leaves.

Your potted parsley is turning yellow because you are overwatering the plant. The excess water is drowning the roots and they are unable to provide nutrients and oxygen to the leaves. The solution is to cut the damaged roots and reduce watering to allow the parsley to recover.

Several other reasons can cause your potted parsley to turn yellow as well. I’ve listed them down and the steps you can take to solve the issue.

Overwatering

The parsley plant is turning yellow because you are overwatering it. The soil should be moist but not wet and if the pot feels heavy, that means there’s too much water in your container or tray.

The excess water will cause the roots to drown leading to fungal problems like root rot. This will kill the roots and they will turn brown or black in color. They will even start smelling due to the fungal rot.

If you find that the leaves are turning yellow even though the soil is moist, it’s probably caused due to overwatering.

You need to dig the parsley plant out of the potting soil and check the roots. If all of the roots have turned black or brown, the plant cannot be saved. If some of the roots are white and healthy, you can still save the plant.

Trim the affected roots using a bypass pruner. Make sure to sterilize it using rubbing alcohol. Throw away the potting soil and clean the pot. You can soak it in a mixture of 1 part bleach and 9 parts water to sterilize it.

After an hour, you can take the pot and rinse it with clean water. Let it dry and now you can add a fresh batch of potting soil to it. Make a hole in the potting soil, place the parsley plant roots in it and cover them up with more soil.

Trim any unwanted leaves and branches from the plant using a sterilized bypass pruner. Now give the potting soil good watering till the water runs out from the drainage holes at the bottom.

Whenever you will water the parsley plant, make sure the potting soil is dry. Stick your finger 1-2 inches in the soil to check for moisture. If the tip of your finger feels dry, it’s time to give good watering to the plant.

Underwatering

If you don’t give sufficient water to the parsley plant the leaves will start turning yellow. The leaves will appear different than with overwatering as they will be dry rather than feeling moist.

This problem usually happens because you don’t know when to water or how much to water the plant. Or you may be forgetting to water the plant.

I suggest you check on your parsley plant every morning to see if it needs watering. Stick your finger 1-2 inches in the potting soil and check for moisture.

If the tip of your finger feels dry you will need to water the plant. Give it good watering till the water drains out from the drainage holes at the bottom.

If you are unable to water your plants every day consider using a self-watering container. If you have several potted plants, you can also set up a drip irrigation system with a timer. It will water the parsley plant at the right time with the required amount of moisture.

Lack of sunlight

The parsley plant requires full sun which means at least 6-8 hours of sunlight every day. If the potted parsley does not get the required sunlight, the leaves will start turning yellowish in color.

This is because parsley plants require high levels of light for photosynthesis and they will produce the chlorophyll required based on the received amount of light.

The solution is to place the potted parsley in a location that will get the required sunlight. If this is outdoors, make sure there is no shade caused by an obstruction such as a wall, fence, or tall plant.

If the potted parsley is grown indoors, make sure to grow it near a window that gets plenty of sunlight. Or you will need to provide some artificial lighting that the plant can use.

Lack of nutrients

The parsley plant has long tap roots that help it extract nutrients deep from the soil. But if you’re growing parsley in a pot, they don’t have that option. You need to provide the required nutrients to the plant.

If the potted parsley does not get the required nutrients, it will start turning yellow as a result. It’s best to add some compost to the potting soil when preparing it.

You can also add some slow-release fertilizer that is rich in nitrogen and will encourage foliage growth on the potted parsley.

Once the parsley has started growing, you can add a little compost or slow-release fertilizer once every month to give it a boost of nutrients. You can also use liquid fertilizer instead but you will need to spray it every couple of weeks because it is absorbed faster by the plant.

Too much fertilizer

If you add too much fertilizer, the nitrogen can burn the roots of the parsley plant. This will cause stress and lack of nutrients in the plant causing yellowing leaves.

You should follow the manufacturer’s instructions on the amount of fertilizer to use and how often

I recommend using organic fertilizer for your potted parsley plant. Because they are absorbed slowly and have less of a chance of burning the roots even if you added a little excess.

Too much heat

The parsley is a cool-season plant that grows best in early spring or late fall when the temperature is between 50 to 70 degrees Fahrenheit.

The best time to start growing potted parsley is after the last frost date has passed. You can start growing the potted parsley earlier if you start seeds indoors.

If the temperature goes higher than 80 degrees, the parsley will be stressed and bolt. The leaves will start turning yellow as a result because the plant will start focusing on growing seeds.

It’s best to grow parsley in the right season to avoid this problem with high temperatures. If the temperature rises for a few days, you could bring the potted parsley to a shaded location away from direct sunlight.

You could also move it indoors where the environment is much cooler so the plant does not get stressed. You could cover the potted parsley plant with a row cover that would shade it from intense sunlight.

Pests and diseases

Your potted parsley plant leaves may turn yellow when attacked by pests such as aphids and spider mites. These bugs will suck the plant sap and cause it to lose nutrients.

You should check on your parsley plant every morning to insect signs of such pests. It’s easy to get rid of them by a spray of water to dislodge them to the soil.

You may also have a problem with diseases which can be caused by too much water or not enough sunlight. The humid conditions will cause fungal diseases to attack the parsley plant. One such disease is Botrytis that will cause the leaves to turn yellow.

It’s best to prevent this problem by avoiding humid conditions near your potted parsley plant. Avoid splashing water on the foliage when you are watering the plant. Only water the base of the potting soil.

Make sure there is good airflow through the foliage of the potted parsley. If the foliage is too dense, it can cause a humid condition. So cut off some leaves and branches. Avoid growing too many parsley plants in a single pot too close to each other.

Poor potting soil

Your parsley plant will start turning yellow because the potting soil is not good. You may have used garden soil that may contain a lot of clay, weeds, and chemicals.

Such garden soil is heavy causing compaction and prevent moisture and air from reaching the plant’s roots.

I suggest using sterile potting soil that is prepared especially for growing potted plants. This will contain the right texture to allow retaining moisture but draining out the excess.

This potting soil will not compact and provide sufficient airflow for the potted parsley plant’s roots.