What Causes Brown Spots on Aloe Vera Plants?

Sunburn

• Ironically, the so-called burn plant is sensitive to direct unrelenting sunlight; indirect light is best for these plants. If the leaves have brown or orange spots, the plant has likely been sunburned. Aloe vera can be moved outdoors for the summer in most climates, but the plant should be introduced to direct light slowly. Even for indoor plants, keep in mind that sun exposure changes direction during the day. For example, a window that has ideal indirect light in the morning could become too brightly lit in the afternoon, resulting in burned leaves.

Aloe Rust

• Aloe rust is a fungus that will cause small brown spots on the leaves of the plant. The spots are the result of the plant secreting a healing compound on affected areas. These spots are permanent, but the disease will not usually spread. Avoid watering the plant above the leaves where water will sit on the foliage. Keep the plant warm and treat with an anti-fungal spray if the problem gets worse.

Tap Water

• The outer skin of the aloe vera leaf is sensitive and should not be overexposed to water (that is, water that sits on the leaves). Also, some concentrations of minerals in tap water can harm the leaves. Tap water varies by municipality, but national guidelines are enforced for basic sanitation. Some tap water contains high levels of organic and inorganic compounds that may be harmful to plants, and some municipalities add fluoride to the tap water. Aloe vera should be watered with spring water or rainwater to avoid bruising or burning the foliage.