Calathea White Star makes quite a temperamental houseplant and can quickly tell something is wrong by curling its leaves.
In any case, leaves curling shows your Calathea White Star lacks the optimum requirement and needs a quick fix before it is too late.
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What Causes Calathea White Star Leaves to Curl? (Reasons & Solutions)
Calathea White Star is a Prayer Plant species from Bolivia’s tropical, warm, and wet forests. They produce curled leaves in response to the unfavorable environment, especially the humidity requirement.
The leaf curling would vary from curling edges and dried crumbly foliage to brown curled leaves.
Here are a few possible reasons why your Calathea White Star leaves are curling and their solutions.
1. Too Much Light
Calathea White Star grows beneath the canopies of tall trees in their natural habitat.
Therefore, they will hardly survive when exposed to full sunlight or brightly lit condition, measuring about 10,000 foot-candles.
Be wary about keeping your Calathea White Star close to the south-facing window or patio, as your plant will be exposed to numerous hours of direct sunlight daily.
The leaves will curl to prevent excess transpiration and begin losing white and green markings.
Besides, further bright light exposure will scorch the leaves, affecting the photosynthesis process and leading to a wilted plant.
How to Treat Light-Stressed Plant
- Start with moving your plant to a low-light area.
- Using a pruning shear, trim badly damaged leaves (excessively crisp and curled).
- Water the soil immediately if the substrate looks dry and crumbled.
- Wait 6-7 days to witness any improvement.
How to Prevent Too Much Light
- Provide low to medium lighting conditions, for example, 250-1,000 foot candles.
- Place the plant at an east-facing window, 3-4 feet away from the south-facing window, or a brightly lit bathroom and kitchen.
- Alternatively, add window filters that significantly cut bright light and UV.
- Keep Calathea White Star indoors under a full-spectrum LED grow light for at least 6-8 hours daily.
2. Low or High Temperature
Temperature extremes are another concern for Calathea White Star because this tropical plant thrives in an ideal temperature ranging between 65°F and 85°F.
Although it loves being dappled in the warm surrounding, anything over 90°F will lead to transpiration.
One of the early signs of transpiration is droopy and curled leaves that look shriveled.
Similarly, a temperature below 65°F, usually during cold draughts, will encourage plant leaves to curl up to keep themselves warm.
How to Treat Temperature-Stressed Plant
- Move your plant away from AC, radiator, and heater as they quickly suck up the moisture in the air.
- Start with removing severely damaged leaves to redirect energy towards new growth.
- If the plant is cold-stressed, move it to a warm location, such as an east or south-facing window.
- Check for overly dry soil, and water it thoroughly to boost the oxygen level available to the roots.
How to Prevent Temperature Stress
- Avoid keeping the plants close to direct light sources in the summer.
- Close the window or move them away from open windows or doors to prevent cold stress.
- Remove them from a room with an air conditioner or heater.
3. Low Humidity Level
The low humidity level is the main culprit for curling leaves in Calathea White Star because this tropical plant thrives in moderate humidity, ideally between 50% and 60%.
The plant leaves will absorb water through open pores on their leaves to maintain the moisture level.
The unavailability of humidity, especially in summer, near AC or a radiator, and in a not-so-well-ventilated room, will encourage it to curl up the leaves.
Remember, leaf curling is a defense mechanism of the plant to retain moisture.
Another sign of a humidity-stressed plant is a dried and brittle leaf surface.
How to Treat Humidity Stressed Plant
- Water the soil thoroughly until the excess water runs out of the drainage holes.
- Mist the leaves using a mister every 2-4 hours for a few days.
- Place the pot on a humidity tray to boost the humidity in the air surrounding the plant.
How to Prevent Humidity Stress
- Install a room humidifier to raise the humidity level in the air.
- Mist the leaves a couple of times every week.
- Mist them early morning to create a fine mist over the leaves.
- Otherwise, huddle the houseplants together to boost the humidity level naturally.
Calatheas do exceptionally well in terrariums, mini-greenhouse, and other sealed environments.
4. Incorrect Watering and Water Quality
Neither Calatheas enjoy overly soggy soil, nor do they thrive in dry soil conditions.
Remember, Prayer Plants enjoy slightly soggy soil conditions to effectively transfer oxygen and nutrients from the roots to the leaves.
Leaving them high and dry, usually during summer, will result in curled-up and crispy leaves. The dry soil condition will encourage excessive transpiration from leaves.
On the other hand, excess water will invite soggy soil conditions, fungal growth, and root rot.
Similarly, using chlorinated or tapwater may lead to a mineral buildup (chlorine, fluorine, and iron) in the soil, entrapping oxygen particles and killing healthy microorganisms.
Mineral toxicity is often indicated by yellowed Calathea leaves that curl up along with the severity.
How to Treat Water-Stressed Plant
- Immediately cut back on watering, trim the heavily yellowed or curled leaves, and let them recover.
- For a dry plant, water the pot thoroughly and let it sit in a warm place to recover.
- Water the plant again in a few days when the soil dries up about 1-2 inches.
- Water the pot thoroughly using fresh or dechlorinated water several times to leach out minerals from the soil.
How to Prevent Water Stress
- Water your Calatheas once a week in spring and summer and once every two weeks in fall and winter.
- Provide about an inch of water every time while watering.
- Use a soil moisture meter or stick your finger into the soil every week to check for soil moisture level.
- Apply a bottom-watering method to let the pot soak the water regularly.
- Always use rainwater or tap water left out in the open for 24 hours to water the plant.
Overfertilizing, especially with excess nitrogen, and damaged roots due to chemical buildup may cause curled-up leaves.
In fact, synthetic fertilizers will significantly damage the leaves by releasing too much nitrogen and salt (Ammonium sulfate, Potassium chloride, and Sodium nitrate) into the soil.
Although you might witness good yields initially, continuous use will lead to salt toxicity.
However, before seeing excessive curling, you will witness excessive yellowing, small new growth, and browning leaf tips and margins.
How to Treat Overfertilized Plant
- Start with trimming heavily damaged leaves to redirect energy towards new growth.
- Flush the soil with fresh water to leach out excess salt and minerals, and repeat the process 2-3 times.
- Place it in a warm location and let it recover.
- Check for root rot if the plant fails to revive within 7-9 days.
- The plant with excessively browned or blackened limp roots must be discarded.
- Otherwise, trim lightly-damaged roots and transplant them in fresh potting soil.
As a preventive measure, fertilize the plant monthly with organic plant food (NPK 10-10-10) diluted to half strength (1-part fertilizer, 1-part water), but cut back in the fall and winter.
6. Pest Infestation
Although rare in houseplants, severe pest infestations may cause curled-up leaves in Calathea White Star.
The sap-sucking insects like leaf scales, mealybugs, aphids, and spider mites will suck the leaves dry, leading to curled leaves.
Pest infestation is common in Prayer Plants grown in high humidity, low temperature, and nitrogen-fed soil.
You would see visible marks and tiny holes in the leaves. As the infestation progresses, the leaves lose mass and curl under their own weight.
Do not forget to quarantine the infected plant before applying any treatment.
How to Treat Pest Infestation
- Start by removing heavily damaged leaves.
- Pick visible pests from the leaves, undersides, and stems and drop them in a soapy water solution.
- Wash the infected parts with insecticidal soap or neem oil to cleanse pests and their bacteria.
- Alternatively, dipping cotton swabs in isopropyl alcohol and dabbing the bugs instantly kill them.
How to Prevent Pest Infestation
- Always use certified, pest-free potting mix.
- Avoid carrying garden plants, dried leaves, and twigs inside the house, which may bring foreign particles.
- Wash the plant with a soapy water solution, neem oil, or horticultural oil every 2-3 months.
- Use a room humidifier to maintain an ideal humidity condition and keep pests away.
- Similarly, avoid using a fertilizer with excess nitrogen and synthetics.
Read more for complete growing and caring guide about Calathea White Star.
Calathea White Star is a lovely houseplant that is equally easy to maintain but is prone to problems.
Care to provide ideally warm temperature, moderate humidity level, weekly watering, balanced plant food, and ample indirect sunlight to keep it healthy.
Once you establish an excellent, caring routine, seeing curled leaves will be a rare encounter.