The sight of an aloe vera plant turning brown, reddish-brown, or orange often leads owners to believe the plant is dying. While the discoloration is a clear sign of environmental stress, it is rarely an immediate death sentence. A brown aloe is typically a stressed aloe, and in most cases, the plant can return to its vibrant green hue once the underlying problem is corrected. This color change is a survival mechanism, indicating the plant is struggling to adapt to its current conditions.
The Science Behind Aloe Browning
The characteristic green color of a healthy aloe leaf comes from high concentrations of chlorophyll, the pigment responsible for capturing sunlight for photosynthesis. When the plant is subjected to severe environmental stress, its survival response includes breaking down some of this chlorophyll to conserve energy.
As the green chlorophyll fades, other pigments naturally present in the leaf tissue become visible, causing the plant to turn brown. These visible compounds are often stress pigments, such as carotenoids or anthocyanins. Carotenoids, which include the red-orange pigment rhodoxanthin found in aloe, help filter intense light and protect the plant’s cells from damage. The appearance of these colors is a form of plant sunscreen.
Identifying the Cause of Discoloration
Pinpointing the exact stressor is the first step toward recovery, as different causes present with distinct visual cues.
The most common reason for reddish-brown or bronze discoloration is overexposure to intense direct sunlight, often called sun scald. Leaves affected by sun stress may feel dry and slightly crispy, with the color change appearing uniformly across the most exposed parts of the plant. Moving the plant to a brighter spot too quickly after it has been indoors can trigger this reaction.
Improper watering presents two different sets of symptoms. An overwatered aloe will display leaves that are dark brown or black, soft, and mushy, especially near the base. This is frequently accompanied by a sour or foul odor emanating from the soil, which signals the onset of root rot.
Conversely, an underwatered aloe will have pale, dull brown leaves that appear thin and shriveled. The tips of the leaves may turn brown and crispy as the plant uses its stored water, causing the tissue to become desiccated. Unlike sun stress, which causes a reddish hue, underwatering leads to a more lifeless, faded brown.
Another cause is cold stress, which occurs when the plant is exposed to temperatures below 50°F (10°C). Cold-damaged leaves typically turn dark brown or black very quickly and may look waterlogged or translucent, feeling soft and mushy to the touch. This damage is often irreversible in the affected tissue.
Steps for Restoring Green Color
Once the cause has been identified, immediate adjustments to the plant’s environment are necessary to reverse the stress response and promote chlorophyll production. If the discoloration is reddish-brown from sun stress, the plant must be moved immediately to a location that provides bright, indirect light. This allows the plant to photosynthesize efficiently without further sun damage.
For an underwatered plant showing shriveled leaves, a deep soak is required; water thoroughly until excess drains from the bottom hole. Future watering should follow the “soak and dry” method, ensuring the soil is completely dry several inches down before watering again. If overwatering is the issue, stop watering immediately and inspect the roots for signs of soft, black rot.
If root rot is present, unpot the plant, and any soft, compromised roots must be carefully trimmed away with a sterile knife. Repot the plant into a fresh, dry, well-draining succulent soil mix and allow it to rest without water for at least a week to allow the roots to heal. For cold-stressed plants, moving the aloe to a stable, warmer location, ideally above 60°F (15°C), is the first step.
Patience is key, as the browning will not vanish overnight. Damaged tissue on the leaves may not entirely revert to green, but new growth emerging from the center should be healthy and green. Over several weeks to a few months, the stress pigments will break down, and the green color will gradually return to the leaf tissue, often fading from the base outward.
When Recovery is Not Possible
While many brown aloes can be saved, it is important to recognize the signs of irreversible damage. If the entire base of the plant, where the leaves meet the soil, is black, mushy, and easily collapses, the rot has likely spread too far. This advanced decay indicates that the main stem is compromised and cannot support new growth.
A completely desiccated leaf that is brittle, papery, and snaps off when touched will not regain its structure or color. In these instances, the affected leaves should be cleanly pruned away to prevent the spread of decay or disease. If the entire plant is compromised, the only remaining option is to salvage any healthy offsets, known as pups, or small, green leaves that can be propagated to start a new plant.