Why Do Leaf Tips Turn Brown?
One of the problems often encountered with houseplants is that the tip of the leaf turns brown, dries out and dies. This problem mainly occurs on plants with narrow pointed leaves, like dracaenas (Dracaena spp.), cordylines (Cordyline spp.) and spider plants (Chlorophytum comosum), but also on certain plants with broader leaves, such as the prayer plants (Maranta spp.) and calatheas (Calathea spp.). Carnivorous plants too are prone to leaf tip necrosis.
Usually when a leaf tip turns brown, it’s because it didn’t receive its share of moisture while the rest of the leaf did… or excess salts have migrated to the leaf. But why? There are several causes.
The 6 Most Common Causes of Brown Leaf Tips
- Dry Air
This is a recurring problem during the winter months. If the air is dry, it’s because we heat our homes and heating reduces the air’s relative humidity. In an effort to compensate, the leaf loses massive amounts of water to transpiration, but as a result the plant’s sap doesn’t make as far as tip of the leaf simply because it is the part farthest from the cells that carry out the job of transporting sap. Since the tip is not receiving enough moisture, it tends to die.
Solution: Increase the humidity by whatever means you choose. Here are some suggestions.
If you apply insufficient water to a plant when you water or if you don’t water often enough, the leaves will be stressed by a lack of water. And again, the leaf tip, being furthest from sap transport vessels, suffers the most, leading to tip dieback.
Plants grown in hanging baskets are more prone to damage than other plants, not only because their foliage is more exposed to drying air (see point 1), but also baskets are typically equipped with only a very small saucer that overflows readily. Therefore the caretaker (you) tends to water more cautiously, thus less abundantly, to prevent spillage, leading to a plant that is constantly suffering from water stress. And again, this kind of stress shows most obviously as damage to the tip of the leaves.
Solution: Water deeply enough to moisten the entire root ball, and repeat when the soil is dry to the touch. If the soil dries out again only 4 or 5 days after watering, it would be wise to repot in a larger pot. As for hanging baskets, instead of watering them sparingly, take the basket down and literally soak it in water so that the soil can truly absorb the amount of water it needs.
As bizarre as it may seem, too much water can just as easily cause brown leaf tips as too little. That’s because, if the soil in the pot is constantly wet, the roots begin to die back.* And if the roots die, less water will make it as far as the foliage… and once again, it’s the leaf tip that suffers most, causing die-back.
*There are few houseplants that are semi-aquatic: they prefer that their roots constantly soak in water, including umbrella palm (Cyperus alternifolius). For these exceptions to the rule, overwatering simply isn’t possible and so won’t cause leaf tips to die.
Solution: For any houseplant that is isn’t semi-aquatic, apply the Golden Rule of Watering: wait until the soil is dry before watering again. To see if watering is necessary, sink a finger into the growing mix up to the second joint. If it feels moist, don’t water. Wait until it does feel dry, then water abundantly, soaking the entire root ball. If the soil mix regularly goes from moist to just slightly dry, you’ll never overwater.
If you fear that your overwatering has gone too far and that the excess moisture has killed the roots of your plant (you’ll probably notice a smell of rot if you sniff the soil), things are more serious. Depot the plant, cut off any rotting roots, repot in fresh soil… and cross your fingers. When the root system of a plant has started to rot, it’s not always possible to save it.
- Contaminated Soil
Over time, mineral salts from hard water and fertilizer accumulate in the soil of houseplants and gradually poison it, causing the roots to die back. If the roots die back, so will the leaves, because they won’t be receiving their full share of water. Again, the leaf tip takes the brunt of the damage. Furthermore, harmful salts tend to accumulate in the leaf tips, worsening the problem.
Solution: Leach the soil of your houseplants at least 2 or 3 times a year or put them outside for the summer so the rain can leach them. And repot regularly, changing the soil when you do so.
If you tend to fertilize too much, you create a situation similar to a soil contaminated with mineral salts: excess minerals tend to concentrate in the leaf tips and cause them to die.
Solution: Learn to fertilize your plants with great care and never to excess. The usual rule for houseplants is to apply fertilizer at a quarter of the indicated rate and even then, only during the growing season.
- Chlorine Damage
Some plants, especially dracaenas, cordylines, spider plants, and carnivorous plants, are very susceptible the accumulation of chlorine in the soil. If your water comes from any kind of municipal system, it probably contains chlorine.
Solution: When caring for plants that are sensitive to chlorine, the best thing to do is to avoid watering with water that contains chlorine. Instead, use rainwater, distilled water, or chlorine-free spring water (you’ll have to read the label on bottled water: some brands contain chlorine, others don’t). Note that leaving the water in an open container for 24 hours before using it to allow chlorine to evaporate is a myth. The type of chlorine commonly used to treat water simply doesn’t evaporate. Here is an explanation.
When the Damage is Done
Once the tip of a leaf is dead (brown), nothing will bring it back to life, regardless of treatment you give to the plant. If its presence bothers you, you simply cut off the dead tip with pruning shears or scissors. But I have an even more laidback solution. I suggest to apply the famous “Laidback Gardener’s 15 pace rule”: step back 15 paces and you won’t see that the leaf tips are brown. Problem Solved!