There are many different varieties of begonias. Some produce flowers, whereas others are beautiful because of their leaves. At times begonias can struggle. Today I will explain the main causes of this occurring and how to bring them back to life.
Overwatering, too much sunlight, soil that isn’t free draining, and the wrong temperature can cause begonias to die. To revive it ensure the soil is damp, don’t put begonia in direct sunlight, and keep the plant where the temperature range is 65 °F to 75 °F (18 °C to 24 °C).
Pests such as insects and mold can be treated with a range of methods which I’ll explain below. I’ll also explain the symptoms to look for to narrow down the cause of your begonias dying. It’s important to note that this article applies to the most common indoor and outdoor begonias.
However, it won’t cover waxy and tuberous begonias. Although most of these solutions do also apply, they can require more specific solutions when they start to die as they grow very differently.
Too much water can cause begonia to die
Most expert gardeners report that overwatering is a common mistake that people can make. In general, begonias like to have damp soil. However, you shouldn’t keep the soil constantly damp.
Symptoms of overwatering are the leaves turning yellow and becoming burned on the edges. This is because when the soil is too damp the roots begin to rot, and don’t uptake enough nutrients or water. The surface of the soil can also develop mold and fungus which can be a bit toxic for houseplants.
- Wait until the top inch (2.5 cm) of the soil is completely dry before watering them again.
- Allow the water to drain out the bottom of the pot by ensuring the holes aren’t blocked.
Too much direct sunlight or not enough sun
Rex begonias have distinctive leaves and are very common indoor plants that can handle low light conditions such as a bathroom. Too much sun can scorch the leaves and cause them to become dehydrated. Not enough sunlight won’t give them the energy they need to grow. This causes them not to grow much at all, and have stunted growth.
- Move your begonias to a bright area that has reflected sunlight.
- Move potted begonias out of direct sunlight in the summer.
- Move begonias into full sun in the winter, autumn, and on cloudy days.
- If required replant or reposition begonias so they aren’t in full shade all of the time.
Too hot or too cold
In winter and summer, the temperature can get too hot or too cold for begonia and they can begin to struggle. In very hot temperatures they can wilt and the leaves begin to dry out too much causing them to shrivel. In cold temperatures, their growth can be stunted as they struggle to distribute water that contains nutrients throughout their stems and leaves.
Begonia won’t typically die unless there is frost or below-freezing temperatures. But, combined with other factors, very cold temperatures can cause the leaves to eventually die.
- Keep your begonias where the temperature will be 65 °F to 75 °F (18 °C to 24 °C).
- Ensure there is good airflow when they are in hotter temperatures.
- Place them where they won’t be subjected to cold drafts.
Various bugs can get out of control and eat more of a begonia than they can regrow. Various mold spores can also survive on the leaves which will feed on the leaves and block sunlight. Insects are fairly easy to spot by visually inspecting the stems and leaves. But pay close attention to the underside of the leaves as well. Mealybugs are a particularly common pest insect on begonia.
Powdery mildew and patches of mold are easy to spot on the surface of the leaves. The good news is all of these are very easy to treat.
- Remove dead leaves and blooms as they develop as it will decrease pest insect numbers.
- Use regular insecticidal soap to keep pest insect numbers down.
- Dab insects with isopropyl alcohol to kill them.
- Use a copper fungicide spray to remove mold.
Soil is too dense or doesn’t hold enough water
Garden soil is generally too thick and sticky for begonias. However, if you have particularly nice and healthy soil that is dark-colored and crumbly it will work well. And it’s generally always best to use potting mix or regular store-bought compost for begonias.
Humid climates mean there is more moisture in the air and it can be necessary to add a bit of perlite to the soil to make it less moist. The symptoms of the soil being too dense or too free-draining are shown in the leaves.
The leaves will become lighter in color and also develop dry edges that are completely dead. This is due to the soil staying wet when heavy and sticky garden soil is used which rots the roots. And not enough moisture staying in the soil profile in the case of sandy soil that is too loose.
- Replant them into potting mix or store-bought compost.
- Add a small amount of perlite for humid climates to soak up excess moisture.
- Use pots with drainage holes.
- For fast-draining soils mulch begonia with organic matter.
Too much fertilizer or it needs more fertilizer
Adding fertilizer to a begonia does increase its rate of growth. However, if you feed it too much fertilizer or give it fertilizer too often it can have the opposite effect. It can cause the fine hairs on the roots to die and reduce their ability to uptake nutrients.
Signs of too much fertilizer are the leaves turning yellow, and having dead spots on the leaves. As well as, the edges becoming light brown and crispy. If a begonia needs fertilizer the leaves will look washed out and/or pale.
- Don’t give them any more fertilizer until they recover.
- Fertilize begonia at least once a year with a slow-release multipurpose fertilizer.
- Avoid fertilizing the begonia more than once every 1.5 to 2 months.
- If over-fertilized, wash off the salts with plenty of water or transplant the begonia into fresh soil.
- Once a year, apply organic matter to the soil around the begonia.