While sunlight is essential for plants to survive, as they rely on light for photosynthesis and the energy needed for growth, plants can still suffer sunburn if exposed to direct, intense sunlight for extended periods. Particularly sensitive plants react with scorched leaves, severe water loss, and stunted growth. In the worst-case scenario, the plant can become so weakened that it dies.
Why sunburn is dangerous for plants
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Cell damage from sunburn: Excessive UV radiation destroys plant cells in the leaves, causing the affected areas to burn, dry out, and eventually die.
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Severe water loss: In direct sunlight, an extremely large amount of water evaporates through the leaves. If the plant cannot compensate for this loss, it will dry out.
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Overheating of leaf tissue: The leaves can heat up considerably, disrupting enzymes and metabolic processes and causing vital functions to fail.
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Impaired photosynthesis: Under heat stress, the plant closes its stomata to conserve water. As a result, it can absorb less CO₂ and photosynthesis is significantly reduced.
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Permanent weakening: If many leaves are damaged, the plant will lack energy in the long term, which in the worst case leads to its death.
Recognizing the signs of sunburn
To avoid long-term damage to your plant, it's important to recognize the signs of sunburn early. Plants in locations with frequent or direct sunlight are particularly at risk. The following symptoms may indicate sunburn:
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Light, bleached spots on the leaves
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Brown spots on the leaves
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Dried or brittle leaf areas
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Partially silvery or metallic shimmering surface
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Sharply defined patches compared to healthy tissue
Especially if these leaf spots only appear on sun-exposed areas – particularly on the upper leaf surfaces or facing windows – sunburn is very likely. In this case, you should act quickly to prevent further damage.
Plant has sunburn: Help and immediate measures
If your houseplant has sunburn, quick action is important. Usually, the first signs of recovery will appear after a few weeks if the cause is remedied and the plant is not exposed to further sun stress. In severe cases, however, a plant may not recover and may die. Therefore, observe affected plants carefully after you have implemented the following measures:
1. Remove brown, withered leaves: Cut off severely damaged or burned leaves with a clean, sharp tool so that the plant can concentrate its energy on healthy shoots.
2. Water the plant correctly: Since intense sun draws a lot of moisture from the plant, it should now be supplied with water evenly and sufficiently, ideally via the roots, without causing waterlogging.
3. Move the plant into the shade: Take the plant out of direct sunlight and place it in a bright but sheltered location with indirect light to avoid further damage.
Does sunburn on plants go away?
The burned areas on the leaves won't heal because the plant tissue is permanently damaged. Brown, withered, or bleached spots will therefore remain. The good news is that if you address the underlying cause, the plant can recover. It will usually produce new, healthy leaves within a few weeks, and its growth will also return to normal.
The right amount of sun: How to avoid sunburn
To prevent sunburn in plants, the right location is crucial. While some plants tolerate plenty of sun, others prefer partial shade or shady spots. However, for most plants, care should be taken to ensure they are not exposed to the hot midday sun.
Furthermore, plants generally have a higher water requirement in warmer temperatures and more intense sunlight. Adjusting the water supply helps to avoid heat stress and keep the plant healthy.
If plants have spent the cold season in a winter location, they should be gradually acclimated to the sun in spring. A direct change from a sheltered spot to full sun can quickly lead to sunburn.
