One of the reasons why phalaenopsis orchids are excellent houseplants is that they thrive in the temperature range most of us can offer them indoors. Prolonged exposure to temperatures outside this range, will surely bring about a host of issues including yellowing leaves. On the other end of the spectrum, constantly exposing your orchid to temperatures above 80 F will overburden the metabolic processes of the plant and cause yellowing leaves, which will progress further if the temperature is not adjusted.
As tropical plants, orchids enjoy moderate temperatures and a humid environment, where the difference between nighttime and daytime temperatures is modest. If temperatures in your home fluctuate too much during winter, you should invest in a thermometer that will help you keep track of seasonal temperature changes that might influence the health status of your orchids. Phalaenopsis orchids rarely receive strong direct sunlight under the canopy of trees in their natural habitat.
Indoors, they thrive in bright indirect sunlight. If your orchid is kept in a windowsill exposure to strong direct sunlight, leaf damage is inevitable. In winter, when strong sunshine is scarce, you can move your plants back to a south-facing window, but in the summer, you should avoid keeping orchids in bright direct light.
Excessive direct sun exposure will cause browning leaf tips and can even damage the roots of the orchid, leading to the eventual demise of the plant if the issue is not corrected. Overwatering is a common threat to all houseplants. Inexperienced gardeners have a tendency to overwater plants out of a desire to nurture and care for their plants. Overwatering is one of the chief reasons for yellowing leaves.
Therefore, one of the first steps in preventing overwatering is picking out the right growing medium for these plants. Soil with a high water holding capacity should not be considered. As most orchids age, the tips beneath the bloom occasionally turn yellow. After some time, the spikes will dry up and drop off by themselves. Alternatively, we can trim them back to the main stem.
Orchid stems may also turn yellow if the plant is not adequately receiving the right proportions of all the nutrients it requires. The two most common nutrient deficiencies synonymous with the yellowing of orchid stems are excess calcium and inadequate nitrogen. Different orchids require different nutrients. Before we uproot or kill any orchid due to a yellow stem, we should adequately research and diagnose the cause. Based on my experience and discussions with friends, here are some reasons why no houseplant owner would love their orchid stems to turn yellow:.
As I have highlighted, the causes of yellowing in orchid stems are different. Where yellowing of the stem is due to overexposure to direct light, the solution is to move the plant to a different position with limited light reach. Alternatively, you can use artificial light that is easy to adjust and control. Excess calcium in the soil causes stem yellowing. In most cases, the extra calcium is introduced into the soil by calcium-laden water. By putting it in a cold room, preferably by the window.
When the sun sets, the heat will reduce, and the resulting cold will induce the orchid to bloom. Next, ask yourself if the temperature is right. Too low temperatures can also cause orchid leaves to turn yellow. Make sure the temperatures around your orchid are between 65 and 80 degrees Fahrenheit during the day and 60 and 70 degrees Fahrenheit at night. If the leaves are wrinkled and listless, the plant is most likely dehydrated. If not, check the roots.
You should only water the plant when the top 1 inch of the potting medium is dry and the roots are white. Make sure there are enough holes in the pot to allow proper drainage. If your orchid is suffering from root rot but you see your plant still has some healthy green roots, trim the rotted roots and repot the plant in new media.
Mist the leaves the first week in place of watering. To avoid overwatering, water your Phalaenopsis orchid with three ice cubes once a week, so that the roots will soak up water slowly. Yellowing leaves could be caused by a fungal infection that starts as yellowing areas on the bottom of the leaves.
If the leaves are yellow and you notice a foul smell, it could be a bacterial infection. In either case, separate the orchid from other plants to prevent the disease from spreading, then use a sterile pair of scissors to remove the affected area. Spray the plant with fungicide to finish it up. What's Wrong With My Orchid? American Orchid Society Website. Growing Orchids.
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