Why are My Bonsai Leaves Turning Black?

Over the years, bonsai trees have become increasingly popular as smaller versions of full-sized trees.

Indeed! bonsai trees look beautiful inside your home or in a Zen garden. However, they have similar nutrients and environmental needs as larger trees.

When bonsai trees are not cared for properly, their leaves may wilt, turn black, or die. If your bonsai leaves are turning black, it is having a hard time. Your bonsai tree needs immediate attention if this happens.

In this comprehensive guide you will learn the reasons for, and the steps you can take to prevent your bonsai tree leaves from turning black.

Ceramic pots are a popular choice for planting indoor and outdoor plants. They come in a variety of sizes, shapes, and colors, and can add a decorative touch to any space. Ceramic pots are durable and can withstand extreme temperatures, making them an excellent choice for outdoor use. They also offer good drainage and can help regulate soil moisture. However, it’s important to choose a pot that is appropriately sized for your plant and to ensure that it has drainage holes to prevent waterlogging. 

Reasons For Bonsai Leaves Turning Black

If the leaves on your Bonsai are getting black spots or darkening, don’t panic! There are a few things you can do to help. Let’s first take a look at some reasons why your bonsai leaves are turning black.

Air Circulation

When you keep your bonsai plant near an air conditioning vent or a heater, it will affect the humidity level. In most cases, excess water does not evaporate at a normal rate. Thus, your bonsai plants end up sitting in water for long periods. 

In this case, it may be a good idea to move your bonsai away from the vent if it is very close to it.

Overwatering

When you first start caring for your bonsai, you become religious about watering it. However, your inexperience can lead to overwatering. 

A simple way to prevent overwatering is to check the topsoil. Check the soil with a finger and if it feels dry, then you might need to water your bonsai.

Underwatering

Underwatering is another couse of black leaves. This can be prevented by watering your plant at the right time. 

If your Bonsai’s top 2 inches of soil are dry, use the bucket trick (usually once a week). This will ensure your bonsai is receiving enough water. 

Infectious black spots

If you aren’t careful, fungus can grow on your Bonsai’s leaves and kill it. If you see singular black spots, then you may need to go to your local nursery to get some Fungicide.

In addition, bacterial infections can drive black spots and browning of leaves on bonsai trees. Bacterial leaf spot is most commonly generated by Pseudomonas bacteria, which flourishes in moist conditions and can be applied by insects. To control bacterial infections, avoid watering the leaves and keep your plants isolated from other infected plants.

Using the spray on the leaves will kill off the fungus quickly. However, if some leaves have too much damage, then you should prune them.

Insect Infestations:

Indoor bonsai plants are liable to insect infestations that can provoke their leaves to turn black. Insects like spider mites, aphids, and scales are most common, they feed on the fluid of the leaves, draining them and leading to discoloration of the leaves. These insects also leave behind moist and sticky remains called honeydew which can generate sooty mold development on the leaves. To get rid of pest infestations you can use soaps made for insects or neem oil as a natural treatment.

Insufficient Light

A bonsai needs 5 to 6 hours of direct sunlight every day. Your bonsai won’t do well with indirect sunlight, unlike some other plants. Hence, it is best to place bonsai with a south-facing or west window.

To give your Bonsai a better chance of surviving and possibly thriving, you should consider investing in UV lighting. For most Bonsai trees, indirect light is simply not enough.

Old Age

It is more likely that your bonsai tree’s leaves are simply aging and dying naturally. When they dry up and fall off, these leaves can turn brown or black on the ends. Only a few leaves may be turning brown or black in this circumstance.

Nutrient Deficiency

Insufficient nutrients, such as iron or magnesium, can lead to black spots or splotches on bonsai leaves. Make sure your plant’s soil is properly nourished. Also, when watering the soil, fertilize it every couple of weeks with a liquid solution.

Too much fertilizer:

Overfeeding can lead to “fertilizer burn,” causing black and browning marks on the leaves. Create a good watering technique, letting the top inch of the potting soil dry before providing it with water again. Use organic fertilizers and follow the instructed dosage to control fertilizer burn.

Salts:

If you notice white spots building up on the upper surface of your bonsai soil, that is generally a salt build-up. Salts can arrive from the water you are giving, the potting mixes, and of course the fertilizers. ‘Flush Watering’ a bonsai tree from time to time will leech out soils and will stop this.

Leaf Burn

If only a few leaves on your bonsai have turned brown or black, you may have leaf burn. As moisture acts as a magnifying glass, sunlight damages the leaves by burning them. To prevent leaf burn, keep your plant away from direct sunlight after misting.

Frost:

Freezing temperatures can harm the bonsai’s vascular function. The xylem carries water and transports it and nutrients from the roots to the leaves, while the phloem carries sugars and additional organic compounds throughout the plant.

When these vascular tissues are injured by frost, it limits the activity of important substances, affecting leaf health. The ruptured cells and disrupted vascular system can lead to the dying of leaf tissue. As the injured cells die, the infected leaves of the bonsai might turn black as a consequence of the system. Cover plants from late frosts by shielding them. You should avoid putting houseplants around cooling gadgets to control further frost damage. Bring susceptible bonsai indoors before the frost strikes your region.

Improper substrate:

The alkalinity or acidity of the soil affects the bonsai’s maturing process. To prevent the appearance of black spots, it’s probably crucial to correct the pH of the soil. You should also ensure that nothing is negatively impacting the roots. When the roots are tightened, it discourages the expected growth of the plant. A rocky substrate can influence root growth negatively. This could be the cause of why the moisture and nutrients it requires are not reaching the bonsai. As a result, black spots arise because it has begun to dry out. Furthermore, a shift in location could be the answer.

My Bonsai Tree Leaf Tips Turning Black, What Should I Do?

If your leaves are showing black tips rather than brown spots or wholly blackened leaves, it is often due to overwatering. If you try one or more of the steps below, you should see improvement.

Water Less

During the warmer months, you only need to water your Bonsai once a week. In the winter, your tree will sometimes require only two to three weekly waterings.

Even though indoor heating can dry out the leaves, they should still be lightly misted. Other than that, don’t water the tree without checking the soil first.

Check the Soil on Each Watering

Make it a habit of sticking the tip of your index finger into the topsoil that surrounds your Bonsai regularly. 

If the top 2 inches of the soil do not contain any moisture, then you can water the plant safely. If the top 2 inches are not dry and moist, leave it alone. Otherwise, the problem will grow worse if you don’t.

Consider Moving the Plant

Your location will affect your water volume. If the sunlight is too filtered, your Bonsai won’t produce enough food and may barely survive. 

If you use a dehumidifier for allergies nearby, your plant might be drying out. Hence, it might be beneficial for your Bonsai to move. However, consider the location carefully.

Avoid placing your plant near vents

If you don’t pay attention to heating and AC vents, they could affect the natural evaporation process, which reduces excess water in the house. 

Additionally, it can make the leaves too moist or too dry. It is advisable to move your plant away from vents if it is directly under one or suspiciously close to one.

Maintain a regular schedule and adjust for the winter

Checking the topsoil regularly will teach you the Bonsai’s unique watering schedule in a very short time. Make sure to water your plant when the top 2 inches of soil are dry, never when it is wet.

Remember that it will need less water in winter, too, and adjust your schedule accordingly.

How To Revive A Bonsai Tree With Black Leaves?

In case your Bonsai has taken a dramatic turn for the worse, it is still possible to save it. You can use this checklist as a starting point to give your Bonsai a fighting chance. Take a look!

Cambium Check

If you scratch your Bonsai tree lightly with your fingernail, you will be able to see the cambium, which is the layer beneath the bark. 

Your plant is still alive if it is green, but don’t worry if you find a few dry spots if there are still green ones.

Get rid of dead sections

You must trim off dead leaves and get rid of any dead branches as soon as possible. When it comes to Bonsai, dead branches are ‘disease factories’, which is why they are very dangerous.

Pick a New Location

It is best to have a south window, but a west window is also a great option for getting proper sunlight. Your plant must receive at least 4 to 6 hours of direct, undiluted sunlight. 

Moreover, you should check the area for vents to ensure that no air circulation hazards will affect water levels.

Prune the Roots

Repotting will be needed if the plant is very badly damaged, so you will have to take care of the roots as a final trimming concern. 

Prepare your potting soil as described below, and then remove your bonsai from the soil. Immediately repot your plant after trimming any dead roots.

Repot the Plant and Start Fresh

The best potting soil for repotting is ‘Boon Bonsai soil mix,’ but you can also prepare your mix at home. In a good home mix, bonsais need a pH level between 6.5 and 7.5:

• 50% Akadama (Japanese hard-baked clay specifically for Bonsai trees)
• 25% Lava rock
• 25% Pumice

How To Prevent Bonsai Tree Leaves From Turning Black?

The best way to keep your plant happy is through preventative maintenance. Therefore, you should create a routine that includes these crucial elements.

Regularly check the soil

A simple test of the soil with your index finger is the secret to growing all kinds of plants. The top two inches of Bonsai trees should be dry before watering, except for a light misting of the leaves if the air is very dry.

Seasonal watering adjustments

In the winter season, you will have to water your Bonsai every 2 to 3 weeks. When it’s colder, you will likely need to check the soil as needed, but you should check it once a week from spring to summer.

Misting is Helpful

In exceptionally dry states, misting is a must. Misting can be helpful even if you have indoor climate control. If you mist your plants’ leaves once a week, your plants will stay happy. Keep a spray bottle nearby.

Fertilize During the Growing Season

Don’t forget to use fertilizer! Fertilize your Bonsai once a week starting in spring until late summer, whether it is deciduous, coniferous, or tropical.

If you notice yellowing of the leaves, reduce the amount of fertilizer; otherwise, only fertilize your Bonsai once a month.

Prune As Needed

Make no apologies for trimming off dead leaves or branches. It’s a GOOD thing to trim dead bits from plants. Otherwise, they are more susceptible to diseases if not maintained. Make sure you have your mini shears at the ready and don’t be afraid to use them.

Conclusion

Taking care of your Bonsai may seem difficult at first, but once you know your plant you will have no trouble. Use your fingers to check the soil for moisture. Also, don’t be stingy with the shears; no dead leaves or branches should remain!

It’s okay to repot your plant if it’s in poor condition. And remember, fertilizer is essential, once a week in the spring and once a month in the summer. 

It won’t take long for bonsai tree leaves to turn black, but if they turn yellow, you’re doing something wrong. Hence take good care of your bonsai tree.
You can contact us on Abana Homes if you need any help with your bonsai tree or if you have any other questions.

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