Also known as oedema, edema is not a disease, nor a symptom of a virus, insect damage or of bacteria. Instead, it is a type of abnormal water retention (or disorder) that is usually influenced by environmental issues. Basically, edema occurs when plants take up more water than needed for transpiration (water loss) from the leaves.
Edema presents differently in different kinds of plants. For example, when bloated cells burst on young fiddle leaf fig leaves they create a reddish pattern of spots over the leaf, while other plants will have a bubbling effect on top of their leaves, or have small white ‘crystals’ on the underside of the leaves.
Mildly affected plants will recover, while severely affected plants may drop leaves and grow distorted new leaves, or even die.
Drainage is key, soils that are compacted and do not drain well are not ideal. To improve the structure and organic content in your soil, break up the soil and add Kings Organic Compost and Kings Sheep Pellets then mix together well.
In heavier clay soils, where drainage is likely to be an issue, sprinkle Gypsum Clay Breaker into the bottom of the hole, this helps slowly condition the soil and will help to break down the clay.
Watering is also crucial to prevent Edema allow the soil in potted plants to dry out by half before applying more water and never allow to sit in any water. For plants in the ground aim to keep the soil moist during the hotter months.
Depending on the cause, there are different ways to treat edema. Keep affected plants on the ‘dry side’ of watering, especially if they are houseplants. Reduce humidity levels and offer better airflow for plants, which may need a little pruning to achieve this.
In severe cases, where most of the foliage has dropped, edema will not be reversible, so it is best to try and prevent it if possible.
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