Often, the direct cause of a houseplant turning red is the plant releasing protective antioxidants called anthocyanins. Used by many different types of plants, these anthocyanins offer protection against too much light, too little water, and other stressors. Many deciduous trees and shrubs will naturally turn red in the fall season as a way of salvaging the nutrients in the leaves before they fall to the ground. Some plants also have leaves that are red when they are new and actively growing, before turning green when the leaves reach maturity.
Indoor houseplants do not go through these same seasonal growth patterns, but their leaves can still turn red as the result of environmental stressors. If you’re noticing some reddening on the tips of leaves, there’s no reason to panic, but you should take steps to determine the underlying cause in case it does threaten the longevity of your houseplants.
Too Much Direct Sunlight
Some houseplants will turn red as a way of coping with too much direct sunlight. Many types of jade plants—which like lots of indirect light and some direct light—are known for turning red in the summer if they start to receive too much direct light. This reddening is usually not the sign of anything serious. In many mild cases, it’s like a summer tan for the plant that will gradually fade back to a lush green throughout the winter. Notably, some people want to know how to make their houseplant turn red. If you like the look of red jades, you can intentionally give your houseplant a sunnier spot and fast-draining potting soil that hasn’t been enriched with extra nutrients.
Water and Temperature Changes
Even in summer, direct light exposure isn’t the only possible cause. If you start reducing watering frequency prematurely, this can prematurely cut off nutrients to the remaining foliage growth and the plant may turn red as a result. Water softeners, hard minerals, and metals can also cause reddening. Similarly, if the plant suffers a temperature shock, especially from warmer to cooler temperatures, the houseplant may turn red. These problems can affect many types of plants but are especially common with jade and jasmine plants.
Soil imbalances can also cause houseplants to turn red. If you’ve added too much fertilizer or if it’s been a long time since you’ve added fertilizer, soil amendments, or fresh potting soil, this could be the culprit. Likewise, if you’ve been tinkering with your soil composition with a new kind of fertilizer or if some kind of contaminant has been introduced to the soil, one of the signs could be leaves that start to turn red.
The key takeaways here are that often a houseplant turning red is nothing to worry about, especially if you’ve been keeping up in general with houseplant care practices. Even still, you should investigate the change in coloration and the circumstances to make sure there aren’t more serious problems that lie ahead.