The jade plant (Crassula ovata) is a popular succulent, but brown spots frequently appear on the foliage, causing concern for owners. These spots are typically the plant’s physical reaction to an imbalance in its environment or care routine. Identifying the specific appearance of the discoloration is the first step in diagnosing and correcting the underlying problem.
Water Stress: The Most Common Cause
The most frequent cause of brown spots on jade plants is a condition known as edema (or oedema), a physiological disorder related to water retention. Edema occurs when the plant’s roots absorb water faster than the leaves can release it through transpiration. This excess water pressure causes the cells within the leaves to rupture, leading to permanent scarring.
The resulting spots are initially water-soaked blisters that eventually dry out, leaving behind hard, corky, rust-colored, or brown patches on the leaf surface. These spots are flat or slightly raised and cannot be rubbed off because they are essentially internal scar tissue. Edema is commonly triggered by overwatering combined with environmental factors that slow transpiration, such as cool temperatures, low light, or high humidity.
Overwatering can also lead to root rot, which presents differently, causing the leaves and stems to become soft, mushy, and translucent before turning dark brown or black. If the stem is soft and mushy, the situation is severe, as the rot has likely progressed beyond the roots. Severe underwatering causes the leaves to wrinkle, shrivel, and develop crispy brown edges as the plant consumes its stored moisture.
Environmental Factors: Light and Temperature Damage
Brown spots can also appear suddenly due to exposure to harsh light or temperature extremes. Sunburn occurs when a jade plant is abruptly moved into intense, direct afternoon sun without a period of acclimation. The intense light damages the foliage, causing the leaves to develop dry, discolored, or brown patches.
These sunburn spots are permanent scars and often appear on the leaves closest to the light source. Water droplets left on the leaves can magnify the sun’s rays, accelerating this burning process. The damage is purely physical and not related to the plant’s internal water uptake, unlike edema.
Temperatures below 40°F (4°C) can cause cold stress, leading to dark, sunken, or black spots on the leaves. Jade plants are not frost-tolerant, and if the water stored in their leaves freezes, the cell walls rupture, causing the affected tissue to become mushy or transparent before turning black. Even cold drafts from windows or air conditioning vents can stress the plant, sometimes causing leaves to yellow and drop prematurely.
Identifying Pests and Fungal Infections
Biological causes for brown spots typically involve insect pests, which are often mistaken for environmental damage. Scale insects are common jade plant pests that appear as small, hard, immobile brown bumps, usually found on the stems and leaf undersides. These bumps are the pests themselves, feeding by piercing the tissue and sucking out the sap.
Scale insects are physically removable, often coming off when scraped gently with a fingernail or a cotton swab. Fungal leaf spot diseases are a less frequent issue for indoor jade plants. When they occur, they look like small, dark, circular spots, sometimes surrounded by a yellow halo, and are associated with cool, damp conditions.
How to Treat and Prevent Future Spots
The first step in treating brown spots is to correctly identify the cause and immediately modify the plant’s care routine. If the cause is overwatering or edema, allow the soil to dry out completely, and then significantly reduce the watering frequency. For sun damage, move the jade plant to a location where it receives bright light but is sheltered from the most intense afternoon sun.
If scale insects are present, they must be removed manually by wiping the affected areas with a cotton swab dipped in rubbing alcohol. Since scars from edema, sunburn, and cold damage are permanent, the affected leaves will not return to their original green state. Pruning severely damaged leaves or stems is recommended to focus the plant’s energy on new, healthy growth.
Long-term prevention requires maintaining a consistent environment:
- Ensure the plant is in a container with excellent drainage holes.
- Use a fast-draining soil mix formulated for succulents.
- Allow the soil to dry out completely between waterings.
- Provide at least four to six hours of bright light daily.
- Avoid placement near cold drafts.