Causes and Solutions for Basil Leaves Turning Yellow

Basil is an herb from the mint family. It is wonderful in tomato sauces, pesto, and on its own as a condiment with cheese and crackers. Basil has a sweet and spicy flavor, rich with earthy undertones.

The plant is easy to grow in home gardens, and the leaves can be used as a cooking herb or added to salads. Basil is a great garnish for any dish, but some folks may be surprised to know that basil can also provide information on the cause of problems with their plants.

Basil is a tender perennial that is grown annually in most climates. Basil is also known as sweet, Mediterranean, or Genovese basil. When the plant leaves begin turning yellow, it indicates that the herb plant has been stressed by something.

How to grow basil

Basil can be grown from seed or cuttings. It is recommended to start the plants indoors before transplanting them to their final location in the garden. Use standard potting soil with a pH of about 6.0 for basil. Cut the stems at about 1/4 inch above the soil surface and allow them to dry for 5 days before planting.

Once it has been cut and the plant has dried, the cut end will start healing. Fill in the hole with soil and water well to begin growing. Once its roots have started growing, stop watering and protect it from frost. If you live in a cool climate, you can start harvesting 3-4 weeks after planting. Basil grows best in full sun but can tolerate various degrees until light shade.

Basil can be harvested by cutting off the stems about 1/4 inch above the bottom of the plant’s leaves so that it does not damage any of the plant’s roots. Removing all the leaves on the basil plant is unnecessary as they will regrow because of the thick roots.

When to Plant Basil

It is sown in the early spring in a greenhouse. Basil loves full sun, so grow it where there is plenty of that. The plant grows best in non-acidic soil, but since basil is a Mediterranean plant, it tolerates acidity.

Basil is a perennial herb and needs warm temperatures for proper growth. It makes great companion plants with peppers, tomatoes, or eggplant.

Basil can be grown almost anywhere indoors. However, basil is a fragile plant and is easily affected by heat and humidity. So grow it in a warm location. It prefers temperatures between 70°F – 90°F with high humidity.

The plants should be kept moist but not watered too often. The leaves will turn yellow if exposed to cold weather or are not watered properly before the frost.

The plant is picked as soon as the leaves begin to turn yellow so that the plant will continue to produce flavor for you for many days. Harvest basil when it’s about 9″ tall because it needs at least 9 weeks to grow back fully so it can produce again later throughout the year.

Problems with basil

In spring, basil leaves are often covered with yellow spots while still green and firm. This is due to the trapping of water on the surface that prevents it from drying completely. Once fully dried out, they turn brown – however, this is not long-lasting as the yellowing will quickly return.

The leaves start turning yellow and begin dropping off; the problem is easily prevented with proper care and by getting rid of insects, plant damage, or diseases. The leaves that wither along with their stem grow very thin and break off at the stem tip. That’s an indicator of drought stress which may also be caused by too much sunlight or temperature extremes.

The following are the causes and solutions for basil leaves turning yellow:

  • Excess water causing root rot:
    Excess water can cause the basil plant to become compact and rot its roots. The most common thing that causes this problem is too much decorative use of water. When the water is sitting too long, the foliage may be yellow or brown as it evaporates quickly. Improper watering may also cause fungal diseases.

    To avoid this problem, water your basil every morning so it will not sit too long. Only water the plant when the soil is dry up to the first set of leaves.

    Basil can also be affected by root rot if you over-water it during transplanting, which forces the roots to grow quickly into a confined soil and exposed to air.

  • Excess fertilizer causing root burn:
    Excess of fertilizer causes burning at the base of the basil stems. When using chemical fertilizers, you will notice that green leaves start appearing, but there are no flowers, discoloration occurs at the base of stems, and leaves turn yellow or brown around their edges.

    Remove the affected plant or plant it in a pot filled with non-chemical organic fertilizer to help prevent damage.

  • Diseases:
    Parasites thrive and cause problems for your plant. The most common pest is thrips, which lays its eggs and white larvae on the basil leaves, thus destroying them. Pear leaves curl; mites and nematodes can also damage basil plants.

    Keep the soil as moist as possible with good drainage but not wet. Remove any affected plant or plant it in a pot filled with organic fertilizer to help prevent problems for your plant since pests are easily passed from one plant to another by hand-to-hand contact or accidental planting using contaminated soil.

  • Potting Mix Too Compact:
    When the soil is too compact and compresses the basil plant’s roots, it will lose water slowly. A good guide on preparing the soil for growing basil is to use a potting mix that has been amended with garden compost and well-rotted manure. It should also be about 80% soil with 20% added components. As the potting mix breaks down, you can use it again, making your plants thrive.

    Easy water and oxygen penetration to reach the plant roots will help avoid those yellow leaves turning brown.

    Work your soil to break up any hard lumps or rocks, and make sure you add plenty of organic matter such as compost and manure to keep the plant healthy.

  • Wrong Soil pH
    When the soil pH has a value that is too high or too low, it causes basil to have yellow leaves. If you have applied lime or fertilizer but your pH is still out of balance, amend the soil with compost and well-rotted manure so that it is more acidic (below 6.0) and add gravel to raise the water level near the bottom of the pot. Through this, the soil retains water and encourages new healthy growth. Soil pH is important because it helps determine the balance of nutrients feeding the plant, such as nitrogen, phosphorous, and potassium.

    You can test for the pH of the soil by using a pH meter, which is not expensive, and you can use it over again. If you want to know how to grow basil, don’t worry about buying another one because many sources will tell you how to do this, and they are easy to find by using the internet or library.

  • Low temperature or inadequate light:
    When the days are short, or there is not enough light, basil will typically turn yellow. It happens because the plant does not get enough sun and will start to grow weak. Only use a well-lit location for basil plants, and if you want to make sure that your plant will continue to grow healthy, then you should use fluorescent lights that are close to the leaves and place them at an angle so they still get full rays of the sun when the weather is cloudy or overcast.

    The best temperature for growing basil is between 60 to 65 degrees. For the best growth of the plant, check the soil temperature, water it with liquid fertilizer, and then allow it to rest for 6 hours before watering again. However, when the temperature is not below 55 degrees, the plant will start to yellow because it is still in its natural environment and cannot be affected by its growth.

    Once the basil leaves turn yellow in a few weeks, you can pick them and use them for cooking or drying. However, you must be aware that the leaves already contain the essential oil, which is the cause of why they are turning yellow. This plant needs plenty of sunshine or light to grow hardy and sturdy.

    As the weather warms up, ensure you are watering the plant regularly and keeping it in full sunlight as much as possible. If you do this, the plant will bounce back quickly.

  • Pests:
    Pests like spider mites and aphids can all cause yellow leaves in your basil plant. Spider mites suck the sap from the plant by rubbing their bodies on it, causing yellowing and leaf drops. Aphids cause similar damage by sucking out the essential oils from the leaves, which usually turn them dark green or black and kill cells on leaves.

    Aphids, spiders, and mites can easily be wiped off using a sponge or cotton cloth. Using a plant spray made especially for pest control is a good idea.

    Termites and other pests are kept by using an organic insecticide like pyrethrin.

  • Lack of nutrients:

    In the absence of the nutrients that are necessary for healthy growth, your basil can easily turn yellow. You are suggested you use liquid fertilizer to ensure the soil is rich in all essential nutrients, promoting healthy growth and preventing any browning of your work.

    Elements that are required by basil in the right proportion are nitrogen, phosphorous, and potassium.

    -Nitrogen is necessary for leaf production; if you don’t supply enough nitrogen, the leaves may become too thin or produce many seeds at one time, causing them to become weak and susceptible to dying.
    -Phosphorous is important as a plant hormone; it encourages plant growth and development.
    -Potassium: it helps the plant to develop properly and stimulates productivity.

    Make sure you are using a well-draining potting mix and good water as well as the liquid fertilizer.
    Also, once you have determined your soil pH level, you can add a bit of gravel to raise the level at the bottom of your pot. The essence of this is to ensure that the bottom of your plant’s roots gets plenty of water with essential nutrients to stay strong and produce new leaves.

  • Overcrowded plants
    When you have too many plants growing in the same place, they can compete with each other and stress the basil. Increasing the size of your pot help to ensure that there is enough room for everything to grow well. Doing this will help your plant stay healthy and strong, and you can enjoy more flavorful and aromatic basil in your meal.

    Add more organic matter to the soil so it is well-drained, and place your plants in a sunny location with plenty of airflows. Take cuttings from new growth to promote a bushy plant that will grow strong and healthy.


The cause of yellow leaves may vary depending on where you live and how your environment is, but if you want to be sure that your basil plants are growing healthy and strong, it is important to pay attention to the environment they are in, what they eat and how they look. You should also wash or wipe off aphids or spider mites using cotton or a sponge with a little insecticide so they will not suck out the essential oils from your basil leaves. You can use cotton swabs dipped in rubbing alcohol to eliminate aphids and their eggs. It is also good to ensure that you keep the plant well-watered at all times, especially when the weather is overcast because that is when the plant needs the most sunlight to keep its leaves strong and healthy.

Many people do not realize that basil needs plenty of sunlight and will turn yellow if it is not getting enough. It’s a good idea to ensure that you water your plant with a liquid fertilizer once every two weeks or so, as well as ensure there is plenty of sunlight. You can also ensure that the soil temperatures are right by checking the soil with your hands and comparing them with your palms. If it’s too cold, add a bit of peat moss on top of your soil and allow it to rest for at least several hours before watering again.

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