Brown Spots on Basil: How to Prevent & Why - Absolute Gardener

Brown Spots on Basil: How to Prevent & Why

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brown spots on basil

vIt’s brown, it’s fuzzy, and it smells like a million bucks. Yes, we’re talking about basil! Basil is a tasty herb that is used in many dishes including pesto and tomato sauce. But have you ever noticed brown spots on your basil? If so, don’t worry – brown spots on basil are totally harmless. This article will teach you how to care for your basil plants so brown spots won’t be an issue! So if you always wondered why are your basil leaves turning brown, keep on reading.

What Causes Brown Spots on Basil?

The brown spots or black spots on basil come from the sun. In fact, anything that is exposed to prolonged sunlight will degrade and brown over time. That’s why most food doesn’t need an expiration date because it has a self-expiration built-in of browning after too much exposure to heat and light!

Another reason for the brown spots on basil is caused by a fungus called Phytophthora. The browning is the result of water droplets, unlike brown patches that appear on leaves from UV radiation damage. This brown spot fungus thrives in warm wet conditions with high humidity levels such as those found within greenhouses or tropical climates.

Other reasons:

Browning on basil leaves can be caused by a number of things such as bacteria or fungi that affect it when exposed to too much water. If basil leaves are exposed to cold or hot water, this can also cause basil plants to wilt and brown.

If you want to prevent the basil from turning brown, make sure not to overwater your basil plant as well as allowing the top inch of soil in a pot (or container) for basil plants to dry out between watering sessions.

When basil leaves do turn brown, it is important to remove them from the basil plant so no other basil leaves will follow. Then you can try one of these remedies:

– Pour boiling water over your basil plants (to kill any bacteria or fungi) and let sit for 20 minutes. Remove basil after this time has elapsed.

– Place basil plants in direct sunlight to dry out.

– Use neem oil on basil leaves, which is an organic pesticide that will kill bacteria and fungus as well as any other pests without harming your basil plant or the environment!

brown spots on basil

Basil Care Guide

Basil plants are finicky. Follow this guide to learn the best ways to care for your plant, so brown spots won’t be an issue!


Soil type is important, basil plants can tolerate sandy or loamy soil but will not grow in heavy clay.

Basil can be grown indoors in pots with soil-free potting mix such as vermiculite. It can also be grown in the garden, but basil must be harvested frequently (every few days) to prevent browning of basil leaves from lack of water due to dry soil or hot temperatures.


Basil prefers morning sunshine but not intense afternoon or evening light, so be sure that basil plants are in a place where they can get the amount of sunlight they need without being left out in the hot afternoons or evenings.


Basil doesn’t like to get too much water, so if you are overwatering your basil it will have a tendency to turn brown due to root rot. Be sure not to over-water basil when planting and make sure there is good drainage in the pot or container that you are growing basil in.


brown spots on basilWe all know basil loves the heat; it’s one of the reasons basil is so popular in summer dishes. But, too much temperature change can cause brown spots on basil leaves. Here are a few ways to prevent this:

– Place your basil plants near an open window that gets plenty of sunlight and make sure they get plenty of water.

– If basil plants are in pots, move the pot to a warmer spot outside on days it’s not raining or cloudy and bring back inside at night when temperatures drop below 50 degrees Fahrenheit (or if your basil is getting too much sun).

– When bringing basil indoors for winter, place basil near a sunny window and pot basil in a container with good drainage so that the basil doesn’t sit too long indoors.


A basil plant needs a lot of water and humidity to grow. Basil should be grown in a well-ventilated area, out of direct sunlight. Consider planting basil near the house or under an overhang to keep it away from damaging humidity. Basil also likes air flow so place basil next to other plants that are more tolerant of high humid conditions like thyme and cilantro.


To maintain basil’s health, fertilise it every two weeks with a water-soluble plant food. This will give basil the nutrients and minerals needed to grow leafy greens and taste delicious.


Basil is not toxic to humans in any way, but for animals like cats and dogs basil can be poisonous. Keep an eye on your pets when they eat basil because it may cause them digestive upset if eaten in large quantities.


To keep basil healthy, it needs to be pruned regularly. This encourages basil’s growth and keeps the plant from getting too bushy or leggy. Pruning should be done when basil is looking a little worn out—when there are brown spots on basil leaves or the plant looks like it needs some fresh air and light in order to grow.

Repotting basil

Basil should be re-potted every year or two. This will keep basil looking young and vibrant by giving it fresh soil to grow in. Basil plants can live for up to five years if they are properly cared for, but may need a new pot sooner depending on texture of the potting mix.

Plant Disease

Basil plants are susceptible to fusarium wilt, which can be identified by wilting basil leaves. This could be caused by a soil-borne disease or the basil being overwatered and stressed out. A new pot of fresh soil will help basil bounce back from this plant disease.

brown spots on basil

Tips for Keeping Basil Plant Happy

You’re excited to use your fresh basil from the farmer’s market, but brown spots have turned up on the leaves. Here are some steps that will help you grow healthy basil:

Check your potting soil to make sure it is well-drained. This means there should be at least six inches of space between the surface of the soil and the top of the pot (or container). If not, add more drainage material like pebbles or perlite to ensure that excess moisture doesn’t pool in your pot and cause brown patches on your plant.

Watering frequency is also important. Allow the top inch of soil to dry out between waterings, and check it with your finger! If you can’t feel any moisture in this area, then it’s time for a drink. Be sure to water the soil and not the leaves of your plant.

These brown spots are harmless, but they’re unsightly when used in a dish! Brown patches can be prevented by following steps one and two above, or you could try adding an inch of mulch around the perimeter of your pot for extra protection from browning due to too much water.

Basil Plant Frequently Asked Questions

Can I eat basil with brown spots?

Yes, basil with brown spots can be eaten. It tastes the same as basil without brown spots and is still safe for consumption.

How do you get rid of brown spots on basil?

Remove the affected leaves and discard them. Gently scrub any remaining brown on your plant away and let the brown spot brown.

What do brown spots on basil leaves mean?

The browning can come about as a result of overwatering, under fertilization, or an infestation by aphids.

How do you treat bacterial leaf spots on basil?

When basil becomes infected by a bacterial leaf spot, it can cause brown spots to form on the leaves or stems. The bacteria that causes this is Xanthomonas axonopodis pv basil and sometimes Pseudomonas cichorii. This disease spreads quickly from plant to plant as water droplets carry the bacterial cells from plant to basil.

However, there are many ways of controlling this disease and preventing it from spreading further in plants:

  • Use a copper soap or dishwashing detergent instead of bleach for cleaning basil leaves
  • When removing brown spots on basil with tweezers, disinfect the area afterwards by dipping the utensils in rubbing alcohol
  • Apply a copper spray to basil plants to prevent further bacterial growth
  • Ensure that there is good air circulation in the basil area
  • Water basil with warm water, not cold or hot water. Cold and hot temperatures can slow down respiration (indoor) which causes leaves and stems on basil plants to brown due to lack of oxygen
  • Ensure there is plenty of sunlight for basil
  • Give basil extra nitrogen by adding compost and commercial fertilizer. This will provide the basil plants with more energy needed for photosynthesis

How can you tell if basil has gone bad?

Basil has gone bad if it becomes brown or black in colour and wilts. It is also possible that the basil will have some slimy patches on its leaves which means they are decomposing.

If you’re looking to eat basil, make sure to cut off any browned parts of the plant before consuming it.

Brown spots on basil leaves safe to eat?

Yes, basil with brown spots are still safe to eat. The basil plant is not poisonous and will simply taste the same as basil without brown spots.


The basil is a popular herb, typically used in dishes with Italian and Asian flavors. Basil can be grown indoors or outdoors in pots, gardens, and small spaces. However, the basil plant is fragile and easy to damage, but it can be saved if you know what the problem is. By following these simple steps for basil care, your basil will start growing again in no time! Planning to purchase basil seeds? Get them here. We hope we’ve helped you with what the tiny black spots on basil leaves are.

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brown spots on basil

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