Why Your Basil Leaves Are Turning Yellow - Backyard Boss
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Why Your Basil Leaves Are Turning Yellow

Basil is the perfect plant to add to your indoor herb garden or vegetable garden as it’s easy to grow, store, and harvest. But, like all plants, basil requires the proper care to continue to thrive. Fortunately, the plant will let you know if something’s wrong, whether it’s an issue with watering, pests, or nutrients.

As with many plants, yellow leaves are usually a sign that something has gone awry. And if you’ve noticed a few yellow leaves on your basil plant, it’s time to take action. In this guide, you’ll learn all the potential reasons your basil leaves are turning yellow so you can stop the issue before it takes over the plant.


Planting and gardening in garden at spring. Person watering planted basil herb in flower pot on table. Organic herbal garden
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Overwatering, which results in excess moisture and potentially root rot, is one of the main reasons for yellow leaves. Basil plants require well-draining soil, though they also like to stay slightly moist. This can be challenging for many gardeners, so there are a few general rules to follow.

First, water the plant around every seven to 10 days, checking how moist the soil is with your fingers before watering. If you plant basil in pots, opt for containers with drainage holes to avoid overwatering. Remember that potted plants tend to dry out more quickly than those planted in the ground, so keep an eye on your container plants when it comes to watering.

Poor Lighting

Basil plant with direct sunlight
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Basil plants prefer at least six hours of direct sunlight per day, so a lack of light may result in yellow leaves. Consider including a grow light or two in your container garden if you’re growing indoors or on a poorly lit balcony. Otherwise, place your pots in the sunniest windows in your home! Proper lighting will also promote healthy growth, making the most out of your plants.


Basil bush with leaves affected by fusarium. Garden plant diseases, farming season
Image credits: Abduramanova Elena via Shutterstock

Plant diseases such as downy mildew, fusarium wilt, and bacterial leaf spot are known through yellow and discolored leaves. Unfortunately, there is no cure for these diseases, so the best course of action is to harvest asymptomatic leaves and garbage the rest of the plant.

Note: while fungicides and disease-resistant varieties are in testing, they’re not recommended/readily available for home gardeners.

Cleaning your pruning shears, watering the base of the plants, and applying mulch can all slow the spread of disease.


Home gardening, cutting herbs with paper scissors
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Like all plants, basil plants need room to grow; if your container becomes too crowded, your plant won’t have access to the nutrients it needs to thrive. You should prune basil plants throughout the season to maintain growth and remove flowers. You can also avoid overcrowding by transplanting seedlings  3 to 4 inches apart or planting a single seedling in a 4-inch pot.


Pests ate leaves on basil plant leaving holes behind damaging the plant
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Pests may be another reason your basil plant leaves are yellowing. Aphids, caterpillars, and spider mites tend to find their way onto basil plants, causing yellow leaves and even issues such as holes. It’s important to catch pests quickly as they can be very detrimental to the overall health of your plants.

Regularly inspect your basil (and other plants) for pests and insects. And if you do spot a few pesky critters, there are several ways to get rid of them. Remember that beneficial bugs, such as bees and aphid parasites, aren’t something you need to worry about, though!

Lack of Nutrients

Repotting and cultivating aromatic herbs at home. Hands in gloves holding fresh green basil plant with roots and soil on background of empty pot and rosemary plant on wooden floor. Horticulture
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Basil plants do best in a soil pH of 6 to 7.5 and require a sparing amount of fertilizer. Still, the plants need nutrients to grow, and a lack thereof may result in yellowing leaves. Check the soil pH before fertilizing since too much nitrogen can cause your basil leaves to yellow, too.

Also, when using a liquid fertilizer on container plants, use 1/2  the recommended strength on the label, fertilizing those indoors plants every three to four weeks and those outside every four to six weeks. Your basil plants may also require repotting as root-bound plants cannot soak up nutrients.

Temperature Issues

Person Holding Basil in Brown Pot
Image credits: Matteo Badini via Pexels

Basil plants thrive in areas where the daytime temperatures are about 70 degrees Fahrenheit, and it doesn’t dip below 50 at night. If you’ve noticed it start to get a little colder outside or have the AC too high indoors, the cold may be affecting your basil plants. Consider keeping them in an area with more sunlight for warmth or in a greenhouse.

Don’t Stop Be-leafing!

More often than not, yellowing leaves are a sign that something isn’t right. Fortunately, proper care is the best way to ensure your basil plants stay happy and healthy.

So, pay attention to watering techniques, lighting, harmful pests, and properly prune, and fertilize the plants! Now that you know what could be ailing your basil plants, it’s time to take action and make the necessary changes.

Have you ever had this issue with your basil plants? If so, what tips and tricks might help other gardeners out? Share in the comments below!