Why Are My Begonia Leaves Curling? (And How to Fix It)


Indoor potted begonia leaves curling

No doubt you love the way your Begonia brightens your room with its vibrant, green leaves and colorful flowers.

However, if you’re reading this, it’s probably because you’ve noticed that the leaves of your plant have started to curl and droop.

The same thing happened to my beautiful Begonia – but I found a way to fix it, and I’ll help you heal yours too!

Begonia leaves curl because of underwatering. An underwatered plant is unable to extract water from the soil and can’t deliver vital nutrients to the leaves. Additionally, excess minerals, caused by overfertilization or hard water, hot temperatures, insects, and disease can make Begonia leaves curl.

Read on to find out what causes Begonia leaves to curl and identify which problem is wreaking havoc with your plant.

Once you’ve found the cause, you’ll be able to get your beloved Begonia back to full health in no time!

Causes of Begonia Leaves Curling

Here are the reasons which are responsible for curling of your begonia leaves.

Underwatering

Underwatering will cause the leaves of your Begonia to curl. As you can imagine, a parched plant is sure to dry out, and one sign of this is curling leaves.

Another issue with underwatering is that nutrients from the soil can’t be carried up to the plant via the water.

Not only does this mean that your plant lacks moisture, but it will also suffer from a nutrient deficiency – cue more curling leaves!

How to Fix

Check the soil of your Begonia plant. The top layer should be dry but the rest of the soil should be moist.

If the rest of the soil is dry, you are underwatering your plant.

It’s worth bearing in mind that begonias appreciate a humid environment.

Even if the soil seems moist enough, they may still not be getting enough water.

To fix this, regularly mist your Begonia as well as watering it in the traditional way. Using a humidifier will also do the trick!

Overwatering

It can seem like a good idea to water your Begonia every day, but you may be doing more harm than good with this well-natured behaviour.

When Begonias are watered too frequently their roots start to rot. This can cause curling leaves as the roots can no longer supply water and nutrients to the plant.

Additionally, overwatering can mean that the water flushes the soil of valuable nutrients.

Instead of allowing the plant to suck up nutrients from the soil, the soil is purged of goodness by the excess water!

Unfortunately, lacking nutrients means curling leaves.

Luckily, overwatering is easy to fix. Follow these simple steps to avoid overwatering your plant:

How to Fix

  1. Only water your Begonia when the top layer of soil has dried out (up to your knuckle if you test with your finger).
  2. Make sure that your Begonia is in a pot with good drainage. If the pot can’t drain well, water won’t be able to escape and will cause root rot.
  3. Plant your Begonia in a light potting mix which describes itself as free-draining. Avoid clay soil as it holds too much moisture.

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Water Quality

Begonia plants can be very sensitive to water which contains too many minerals, chemicals, or too much salt.

A lot of the time we aren’t aware of the minerals or chemicals that are in our tap water, but it’s not uncommon to find added chlorine or fluoride in there.

As well as added chemicals, some areas have water which is naturally “harder”. Hard water has a higher mineral and salt content.

Chemicals, or high mineral and salt levels, found in water can cause damage to a Begonia plant. They burn the plant from the inside, which leads to dry and curling leaves.

How to Fix

Even if you live in an area with soft water, chemicals in your tap water could be causing your Begonia’s leaves to curl. Consider trying one of the following:

  1. Collect rainwater. If you can collect rainwater, you can use it to feed your Begonia. This is a great option because rainwater doesn’t contain any of the harsh components that make leaves curl.
  2. Buy distilled water. Distilled water has been filtered and is a much better option for your Begonia than tap water.
  3. Use a water filter. Water filters that use carbon blocks will remove unwanted minerals and chemicals from the water making it safer for your Begonia.     

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Excess Fertilizer Application

Begonias require a balanced fertilizer which supplies them with equal parts nitrogen, phosphorus, and potassium.

It is possible to overfertilize Begonias with the wrong type of fertilizer or by fertilizing too frequently.

Begonias require diluted fertilizer in a ratio of 1-part fertilizer to 3-parts water. If they are overfertilized then a build-up of salt can occur in the soil.

Too much salt will have several negative effects on your Begonia.

It can kill the micro-organisms in the soil which are beneficial to your plant, as well as burn its roots.

As a result, your plant will lack nutrients because the roots are unable to extract them from the soil.

A Begonia which is showing signs of overfertilization will exhibit browning, and the ends of the leaves will start to curl.

How to Fix

  • Use a balanced fertilizer like 10-10-10 to make sure that your Begonia is receiving nutrients in equal measure. An overload of one nutrient will inhibit the plant’s ability to absorb the others.
  • Dilute the fertilizer using 1-part fertilizer for every 3-parts water. Using neat fertilizer will be too strong for your Begonia.
  • Fertilize your plant once a month. More frequent fertilization will cause the leaves of your Begonia to curl because fertilizer also contains salt. If your plant ingests too much salt the leaves will dry out.

Lack of Nutrients

Begonias rely on a combination of nutrients to stay in good health.

An equal balance of nitrogen, phosphorus, and potassium is needed to keep Begonias happy.

If these nutrients are lacking, or if the plant is not able to absorb them efficiently, the Begonia will start to look sick and its leaves will shrivel and curl – a very sad sight!

How to Fix

You can take a few steps to ensure that your Begonia is getting the nutrients that it needs.

  1. Make sure to fertilize your plant once a month. Use a balanced fertilizer that will provide equal parts nitrogen, phosphorus, and potassium.
  2. Check the pH of your Begonia’s soil. If the pH isn’t correct your Begonia will struggle to extract nutrients from the soil, even if they are present!
  3. You can test the pH of your soil at home using a home-testing kit.
  4. Begonias like the soil to be pH 6.5.
  5. Add lime to raise the pH level, and sulfur to lower it.

Temperature Stress

Begonias appreciate temperatures that are on the cool side. The optimum temperatures for them are between 58 – 72°F (14 – 22°C).

Not only do Begonias like to be kept at a specific temperature, but they can go into shock if the temperature changes too quickly.

This can be caused by natural temperature changes or the presence of a draft or heating.

If your Begonia gets too cold, its roots won’t function well. They will struggle to bring nutrients up into the plant.

If it is too hot, your plant could quickly become underwatered and the leaves may get scorched.

If the temperature changes too quickly and your Begonia goes into a state of shock, the natural processes of the plant will be interrupted.

All of the above scenarios can cause the leaves of your Begonia plant to curl.

How to Fix

Try to keep a thermometer on hand so that you can check the temperature of the room where you keep your Begonia.

If the temperature falls below 58°F (14°C) consider moving your plant to a warmer room, perhaps one with fewer windows and drafts.

When temperatures rise above 72°F (22°C), it’s time to take measures to cool your Begonia down.

Move your plant to a cooler room and consider opening windows in the mornings and the evenings to allow in colder air.

Avoid stress caused by temperature changes by not suddenly turning on the heating or air conditioning near your Begonia.

Light Exposure

Most varieties of Begonia like to be placed in partial shade and indirect sunlight.

Direct sunlight can cause damage to your Begonia’s leaves by scorching them.

It can also make the soil of your Begonia dry, causing your plant to become parched.

The leaves of a scorched or parched Begonia plant are prone to curling as they get burnt and dehydrate.

The roots of a dehydrated plant are not able to provide sufficient water and nutrients.

If your Begonia doesn’t get enough sun light, it will not be able to carry out photosynthesis. This process allows the plant to use light to turn nutrients into food.

If there is a lack of light, your plant will struggle to grow and will become weak and flimsy.

The leaves of your Begonia will suffer: their growth will be stunted, they will turn brown, and you will notice them drying and curling.

How to Fix

You can easily fix the problems caused by light exposure by following these steps:

  • Make sure your Begonia is not sitting on a windowsill that receives direct sunlight.
  • Don’t hide your Begonia away in the dark. Place it in a room that is bright during some parts of the day and shaded during others.
  • Consider using sunshades on the windows if you worry your Begonia is directly in the sun and you can’t move it elsewhere.
  • If there is not enough light, you can use an artificial plant light to mimic sunlight. This will assure that your Begonia is able to carry out photosynthesis. 

Pot Size

Begonias need a pot of about 6-8 inches (15 – 20cm)per plant. If the pot is too small their roots will not be able to grow properly and will get rootbound.

When roots become rootbound they are unable to transport essential water and nutrients to the body of the plant.

A pot which is too small also can’t hold a sufficient amount of nutrients in the soil.

If the Begonia is too big for its pot, it will quickly use up the nutrients in the soil and develop a deficiency.

If your Begonia is in too large a pot it may become waterlogged. This happens because the soil retains too much water and the plant can’t make use of it.

Often, this will lead to root rot because the roots of your Begonia will be sitting in water for too long.

Transplanting into too large a pot too quickly can also cause problems. Pots should be upgraded one inch (2.5cm) at a time, as the plant grows.

Using a large container too soon will result in fertilizer, nutrients, and water being too sparingly spread out in the soil.

Damaged roots and nutrient deficiencies will cause the leaves of your Begonia plant to crinkle and curl.

How to Fix

  • Measure the size of your planter. If it is smaller than 6-8 inches (15 – 20cm)then you need to transplant your Begonia to a bigger pot.
  • Don’t increase the size of the plant pot by more than one inch (2.5cm) at a time. Doing so risks sizing up too quickly which will cause problems for your Begonia.
  • If in doubt, measure the size of your Begonia’s roots and choose a pot that will is two inches (5cm) larger on either side.

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Diseases Can Cause Begonia Leaves Curling

Begonia stem and root rot is a fungal disease which may affect your plant.

This disease is spread through moisture and can be activated by damp ground and cool weather.

If your Begonia is infected with this disease you will notice that the stem starts to droop and collapse.

This fungus causes water retention in the stem of the plant and causes damage to the stem, branches, and leaves. As a result of this damage, the leaves will wilt and curl.

How to Fix

Begonia stem and root rot is not very common, but if your plant is infected unfortunately there is no cure.

The best course of action is to dispose of your plant and to start again.

To avoid fungal diseases, I advise you to follow these preventative measures:

  • Disinfect your pots before using them.  
  • Sterilize all tools before use. This disease can also take hold via the stem and leaves, not just the roots.

Therefore, watering cans, misting spray bottles, etc. should be sterilized in case they may contain spores of the fungus.

Begonia Leaves Curling Due to Insect Infestation

Aphids are the biggest insectile threat to Begonias. They feed on the leaves of the plant and leave behind a substance which causes mould to grow.

Aphids steal nutrients from the plant, weakening it and causing damage. The mold they leave behind interrupts the process of photosynthesis.

As a result, your Begonia will struggle to turn nutrients into food and will start to shrivel and suffer.

Other insects can cause problems for your Begonia, although it is less common to have an infestation of them.

Slugs, snails, and caterpillars chew through leaves and this damage causes the leaves to die.

How to Fix

If you suspect you have an aphid infestation you should look out for the tell-tale signs.

They leave a sticky black substance behind on the leaves which should be easily identifiable.

  • Often, water alone will work wonders in washing aphids from your Begonia.
  • If you have a larger aphid infestation, you may have to spray insecticidal soap on the leaves.

Slugs, snails, and caterpillars are easily removed by hand.

It is unlikely to find an infestation of these insects on a house plant and removing the single offender should solve the problem.

How To Prevent Begonia Leaves Curling

Overwatering, inadequate water quality, and light exposure are the main culprits for causing the leaves of your Begonia to curl.

Often, all that is needed is to check the amount, and quality, of water being fed, as well as the position of the plant. Easy!

Diseases or insect infestations can also cause leaves to curl. These can be treated with specific products and are often simple problems to fix.

To prevent diseases in the first place, proper sterilisation of pots and equipment will stop the potential spread of fungus and disease in its tracks.

In addition, it’s a good idea to keep an eye on the size of your Begonia’s pot to make sure it’s the right size for your plant.

It’s an easy problem to solve and could make a world of difference.

FAQs

Why are my Begonias wilting?

Begonias may start to wilt for one of several reasons. The main cause of wilting is underwatering.

However, overwatering, bad water quality, problems with light (either too much or too little), and the wrong pot size can also cause Begonias to wilt. 

How often should I water my Begonia?

Begonias do not generally need to be watered every day. As a rule, you should water your Begonia when the top layer of soil (up to your knuckle) is dry.

This will avoid overwatering and is a good way to work out when to water your plant.

Do Begonias like sun or shade?

Begonias like a combination of partial shade and indirect sunlight. For example, a bright room which receives a few hours of sun per day.

It’s best to avoid placing your Begonia in direct sunlight as they don’t like high temperatures and it can cause them to dry out.

Conclusion

You’re now well equipped with all the necessary information to bring your lovely Begonia plant back to full health.

Have you found that the leaves of your Begonia have started to curl? Which tip helped you to restore your plant?

Arifur Rahman

I'm the owner of gardenforindoor.com. After completing my bachelor of science in agriculture, I'm serving as a civil service officer at the Department of Agricultural Extension, Bangladesh. I started Garden For Indoor to make your indoor gardening journey easy and enjoyable.

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