Leaf tipburn is a troublesome condition that sometimes appears on certain species of houseplants. It is characterized by the browning of the tips (and margins) of leaves, while the remainder of the leaf remains healthy. New leaves may look normal when they emerge, but as they mature the tips will gradually develop the same symptoms. While tipburn is not a condition which indicates the plant is necessarily doomed, it does detract from its decorative appeal.
Depending on environmental circumstances, some plant species are more likely to develop tipburn than others. For example, members of the lily family are prone to develop tipburn even under relatively good growing conditions. For other species, tipburn usually is associated only with poor growing conditions.
Tipburn is not a disease. This means that it is not caused by plant pathogen such as a fungus, bacterium or virus. Rather, it is an abiotic plant disorder that most often is the result of one of three causes: 1) excessive fertilizer application, 2) improper watering, or 3) fluoride toxicity. Members of the Liliaceae plant family are especially sensitive to fluorides which is why they often develop tipburn even when properly watered and fertilized.
Once the tip of a leaf dies, there is no way to return it to its normal appearance. While clipping off the dead portion of the leaf is one possibility, preventing tipburn is a more logical and practical alternative. First, fertilize houseplants according to the recommendations found on the label of the fertilizer package. Most houseplants grow very slowly and need relatively little fertilizer compared with outdoor plants. During winter months, most authorities recommend not to apply any fertilizer to houseplants that do not receive supplemental light, since growth has nearly stopped due to the short, "dull" days of winter.
Do not let fertilizer salts build up in the growing medium. After fertilizer application is resumed in the spring, catch and empty drainage water from the plant's container to prevent "wicking" fertilizer back into the pot. The presence of a whitish residue on top of the growing medium indicates that the medium should be flushed with clear water. Also, never water houseplants with water that has passed through a water softener. This practice tends to add to the problem of excess salts in the root zone of the plant.
Second, while more houseplants are killed from overwatering than from any other cause, do not allow houseplants to become too dry. As a potting mix dries, it loses water but not the fertilizer salts in the "soil solution." This tends to increase the salinity of the root zone and mimics the problem of excessive fertilization. Additionally, the soilless growing media used to grow houseplants today tends to have more "bound water" which is unavailable for plant uptake, compared with potting soils of yesteryear. As a general rule, most houseplants growing in a soilless medium should be kept uniformly moist, but not wet.
Finally, for plants sensitive to fluorides, start with a growing medium free from perlite and water only with rainwater or distilled water. Perlite contains fluorides. Therefore, companies that formulate and market growing media often offer perlite-free blends for sensitive plants. Additionally, many public water sources contain trace amounts of fluorides. Given enough time, sensitive plants can accumulate enough fluorides from this water to develop toxicity symptoms. Keeping the pH of the growing medium somewhat high also can be lessened the severity of fluoride toxicity, since fluorides become less available for uptake as the pH of the growing medium rises.
REVISED: January 25, 2021