If you are into gardening and have ever owned a plant, you may have heard of bonsai. To make it clearer for you, bonsai is the Japanese art of growing and training miniature trees into pots. With Bonsai, you just want a miniature version of a given tree in your home.

Now that we know what a bonsai is, we need to know that these are extremely delicate plants and have to be taken care of. One of the most common issues faced by people while growing any kind of plant is that the leaves turn yellow.

Let us talk about what might be the problems your plant is facing and how can you deal with them.

Why do the leaves turn yellow?

Bonsai leaves generally turn yellow if the plant you own grows throughout the year. This is what happens with any full-sized tree in the autumn. If it is not autumn or you own an evergreen plant, yellow Bonsai leaves could be conveying a message. 

Your trees are having issues with the care it is receiving. These issues might be related to nutrition deficiencies, overwatering, cold air, trimming, or stress.

Let us talk about the problems your beloved green friend might be facing:-

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Underwatering 

The first and probably the most common mistake that plant owners make while gardening is about the water that they provide their plants with. Providing your plant with less water than it needs might be the leading cause of leaves turning yellow. 

Bonsai trees need their roots to be soaked to thrive, but make sure that they are drenched, not drowned. 

Some other symptoms that will help you know if your plant is underwatered include, the wilting of the leaves, followed by the browning of the edges of the leaves. The appearance of the leaves starts changing, with a crisp look that ruins the entire aura the plant holds. 

This can also be followed by the stunted and slow growth of the plant and the soil pulling itself from the corners of the plant.  

How to deal with the issue?

Conduct the finger test on your bonsai daily to ensure that you are watering your plant enough. Stick your finger, knuckle deep, in the soil. If the soil on top feels dry, then your bonsai is in the need of watering. 

To water the plant properly, first soak the top layer of the soil in the liquid to make sure that the soil absorbs enough of the water to get to the roots. Then pour water liberally into the entire pot. Give it time to soak before you start pouring more.

More often than not, water ends up draining from the sides of the pot and missing the roots entirely since the soil tends to be looser on the side. You can pay attention to watering till you see the water seep out of the draining hole.

Overwatering

bonsai-watering

Another issue that is quite commonly raised with regards to improper care of a plant is overwatering. Overwatering is when the plant receives more water than is necessary for its survival and growth. 

Many of you might think “what can be so wrong with that? At least the plant will have something in the reserve.” You need to know that you are very wrong. 

Bonsai are tiny plants and do not have enough space to “reserve” the said water. The water just ends up clogging the pot, and ultimately to the decay of the roots. 

A few other symptoms, in addition to the yellowing of the leaves, might include wilting and drooping of the leaves. If you smell a foul odor when you walk near your plants, it is safe to assume that the roots might be rotting below the surface of the soil. This can also cause some sort of fungal growth in your plants. 

If you see blisters or abnormal growth on the undersides of leaves, it might be an indicator of plant cells that have burst because they contained too much water.

How to deal with the issue?

To deal with overwatering, you can first start by planting your bonsai in proper potting soil and using the right kind of container/pot. The steps of preventing overwatering are very similar to that of underwatering.

Before you pour water into the pot, make sure that you check the soil for moisture before doing so. This can also be done using the finger test. Make sure that you do not water the leaves otherwise, they will develop mold and lose their beauty. 

Watering during the day is known to help the plant because during the sunlight hours, the excess moisture can evaporate with ease. Also, you can drain the excess water in the pot by tipping it over. 

Lack of sunlight

Adding to the list of problems the plant might be facing when its leaves start turning yellow, is lack of exposure to sunlight. Like the bigger version of the tree, the miniatures also need a large amount of sunlight to survive and grow well. 

The chlorophyll in the plants is responsible for turning the leaves of the plant green. When the plant doesn’t receive the right amount of sunlight, the plant stops producing sufficient chlorophyll thus turning the leaves of your beloved bonsai yellow. 

Any bonsai needs approximately 5 hours of sunlight exposure, direct or indirect, to grow properly and remain healthy. Although this might vary depending on the species, 5 hours is usually the minimum time they need to spend in the sun.

indoor-bonsai-position

How to deal with the issue?

The most rudimentary solution to this is exposing your plant to more light. If you feel the temperature is not right outdoors, you can try keeping your plant near the window so that it receives indirect sunlight at the very least. 

If the house is in low light condition anyways, try using magic mirrors to brighten up the dimmer corners of your house. Place these mirrors at an angle where they can expose your plants to the right amount of sunlight, in the most effective way possible. 

One can also try to use hanging planters for extra space and lighting. Plants that happen to be small enough to fit in a hanging planter take advantage of being able to get more customized lighting solutions.

One can also go ahead and opt for a simple artificial lighting solution in the form of LEDs and other specialized products that help with your plant.

Trimming or Wiring

One of the most prominent features of bonsai is the fact that you can go ahead and shape them as per their liking. Shaping of the bonsai can be done by trimming and wiring the plant. 

Trimming is when the branches and leaves of the plant are clipped in a way that helps shape it. Wiring, on the other hand, is when the plant is tied and shaped using copper wires while it is still young so that it grows in a certain manner. 

Now when you do this, you need to be extremely careful because if this is not done right, you might damage the plant. 

Sometimes, when the plant is over-trimmed, or not trimmed in the right manner, the bonsai might feel stressed. When the plant feels the pressure, the leaves start to lose the green color and develop a yellow hew to themselves.

Similarly, if the plant is wired before it is ready to be wired you may hinder its growth spurt. If you hinder the growth spurt, the plant will is more likely to get diseases and pests and develop a brittle bark, which might result in its breaking. 

Pruning

How to deal with the issue?

One of the right ways to address the issue is knowing what you are doing and when you are doing it. With regards to trimming, know what branches and trees need trimming. Don’t go about cutting and shaping the plant in any random manner or you’ll end up ruining your bonsai. Prune them only when they are in the dormant stage and use sterile shears.

Even with regards to wiring, try and ensure that you do not wire the plant while it is still growing. If that happens, your tree might develop a brittle bark. Also, don’t tie the wires in a manner that they start digging into the bark of the tree. 

Remember to remove the wire from the plant during the same season that it is put on the plant.

Fertilising and mineral imbalance

Something that we are all aware of is the fact that plants need minerals to grow. They get these naturally, but a safer option is to add some fertilizer to help facilitate the growth of the plant. 

But sometimes, this plan might backfire. If the content of a particular nutrient or mineral exceeds the required amount in a plant, it will damage the plants and the leaves of the said bonsai might become yellow. 

This happens when there is an excess of a certain mineral substituting another, when is a huge quantity of one mineral and not enough of another. 

ficus bonsai fertilizing

How to deal with the issue?

You can check the mineral levels of the plant using a soil testing kit. They are available at most gardening stores or you can order them online. These tend to be fairly accurate and help the plant a lot.

Another point to keep in mind is the use of the right kind of fertilizer with your plant to minimize the problems that you might face. 

Also, adding the fertilizer at the right time helps your plant. Try adding fixed amounts of fertilizer every 7-10 days when the plant is facing the growth season. You can fertilize your bonsai approximately a month apart during the dormant season. 

Make sure the fertilizer that is used is specially crafted for bonsai.

Stress

Like every living being, a change in the environment might be troublesome for your plants too. When your plant is being repotted or endures a general environmental change, it might feel a little stressed. The situation is usually temporary, but if you don’t handle it with care, your plant might get yellow leaves. 

You need to make your plant feel comfortable about the change that it is enduring so that it recovers from the stress as soon as possible. Although repotting is often considered a necessity for plants, you need to make the change as smooth as possible to help your plant survive.

How to deal with the issue?

When you are repotting your plant, make sure you use the right container, which is a little bigger than the last one, allowing the plant a little space to grow. Also, don’t change the soil that it is being grown in while repotting or your plant might have difficulty adjusting.

Similarly, if you are trying to change the environment of your bonsai, make sure you do it when the plant is a little hardened to the surroundings in general.

Nutrient deficiency:

As bonsais are confined to small pots with limited soil, a lack of nutrients may happen. Some nutrients are extremely transportable. Nitrogen, for instance, drives through soil smoothly and drains away. Unless soil nitrogen is frequently replaced through fertilizer applications, nitrogen deficiencies turn bonsai leaves yellow or pale green. 

If you suspect nutrient shortages, good fertilization, and premium bonsai plant nutrition can be beneficial. Your regional county extension agency can also give information on the precise nutrient status of your soil. But through the yellowing process of the leaves, you can determine which nutrient is causing this. For example;

Nitrogen deficiency:

Nitrogen encourages green, leafy growth of the bonsai, and lack of it ends up in yellowing of the leaves and stunted growth. Nitrogen is extremely soluble, so it gets rinsed out of the soil during watering sessions, leaving the soil lacking it in the active season if neglected, just when plants are putting on fresh growth. Insufficient nitrogen in the soil is a common reason for yellow leaves in spring.

Detection:

Shows up as a typical yellowing. Older and inner leaves turn yellow first. As it spreads more, yellowing also spreads outward, ultimately getting to the young leaves, too. 

Remedy:

For a quick recovery, using high-nitrogen fertilizers such as sulfate of ammonia or poultry manure pellets will fix the issue.

Potassium deficiency:

Potassium is required for maintaining both moisture uptake and the method of letting plants harness fuel from the sunlight for photosynthesis. Potassium stimulates flowering and fruiting production and general hardiness. Deficiencies are more possible caused by light, sandy, or chalky soils where potassium can smoothly drain out of the pot.

Detection:

The edges of the leaves turn deep yellow, but the inner leaf remains green. Older leaves display signs before the younger ones, and leaf edges shortly turn brown.

Remedy:

Use high potassium fertilizers such as sulfate of potash, A potassium-enriched liquid fertilizer to promote flowering and fruiting in bonsai plants. Make sure to follow the instructions on the package. 

Magnesium deficiency:

Magnesium in soil is required for lustrous leaves and for bonsai to obtain energy from the sun. Soil deficiencies of magnesium are more typical on light, sandy soils. Over-usage of high-potassium fertilizers can induce magnesium deficiency, as plants accept potassium in preference to magnesium.

Detection: 

You will notice yellow patches between leaf veins on matured leaves. Veins remain green as yellow moves from the leaf inside out. Edges of the leaves turn yellow at the end.

Remedy:

For quick recovery, apply Epsom salts as a foliar feed. Weaken the effect by diluting the salts in water. You can also add a few drops of liquid detergent. Apply two or three times a month.

Iron deficiency:

Iron deficiency is also typical when soils are relaxed, increased in calcium, badly drained, or wet and when root health is damaged by root rot pathogens, nematodes, or other natural or biological reasons. 

Detection:

You will notice the yellowing between leaf veins, but it strikes new leaves on the top of the plant and affects the branch tips first.

Remedy:

Iron-reached fertilizer will help. Also, mulching can provide numerous benefits in addition to improving nutrient availability. 

FAQs

Can the issues faced by big trees and their bonsai versions be the same?

Yes. Like the tree and the bonsai usually need similar conditions to grow, they might face the same problems too. Pests, rotting roots, etc. might affect both of them. 
However, you have to know that the miniatures are often more delicate than the trees so the trees might have more endurance for the aforementioned problems.

Can your plant die because of yellow leaves?

Yellow leaves might not be the root cause of the death of your bonsai. But the underlying cause of yellow leaves, like pests, decaying roots, stress, etc. if left ignored for a long period, might kill your beloved bonsai.

Can I fertilize my plant when it is recovering from overwatering?

Once you’ve started your plants’ rescue from decaying roots, avoid watering or fertilizing them again until you’re positive it’s going to survive.

Conclusion

Bonsai trees are a little hard to care for but a few tricks and careful observation can make the process easier than you might imagine. Of course, you might have to face a few bumps along the way, but life is not a bed of roses, and neither is gardening.

 All you need to do is keep a keen eye on your plant, and keep broadening your knowledge about it so that your plant lives a long and happy life with you!

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