Prayer plants are a popular and relatively easy to care for houseplant. They are known for their unique habit of curling their leaves up at night, then unfurling them again in the morning. This distinct behavior is what gives prayer plants their common name. But why exactly do prayer plants curl their leaves at night? There are a few key reasons.
To Conserve Energy
One of the main reasons prayer plants curl their leaves at night is to conserve energy. By curling their leaves upward, prayer plants reduce their surface area that is exposed to the air. This helps limit water loss through transpiration. Curling the leaves also protects the plant from excessive cold or heat at night when temperatures may drop or fluctuate. Reducing water loss and protecting the leaves from temperature extremes at night helps prayer plants preserve energy and moisture.
To Protect Themselves
In their native tropical habitats, prayer plants grow on the floor of rainforests. At night, folding their leaves upward may help protect the plant from being trampled by foraging animals in the dark. Curling the leaves upward also hides the underside of the leaf, keeping insects off of the more delicate undersides. The upward position may also make it harder for pests to take bites of the leaves or lay eggs on the plant. So curling up at night serves as a protective mechanism.
To Maximize Photosynthesis
By sleeping with their leaves curled up in a vertical position at night, prayer plants are able to quickly unfurl them flat in the morning to maximize light exposure and photosynthesis when the sun comes up. If the leaves were left flat all night, it would take more time and energy to arrange them perpendicular to the morning rays. Having the leaves pre-positioned vertically enables the plant to get a jumpstart onphotosynthesis as soon as daylight breaks.
How Prayer Plants Curl Their Leaves
Prayer plants curl and uncurl their leaves due to naturalcircadian rhythms, which are internal clocks that regulate biological processes over a 24-hour cycle. Here is how this clock works in prayer plants:
The Role of Light
Light is one of the main influences that regulates prayer plants’ circadian clocks. Prayer plants generally start to curl their leaves upward around dusk as light diminishes. Low light signals to the plant that it’s nighttime.
The Role of Plant Hormones
In addition to light cues, prayer plants curl their leaves due to changing levels of hormones that fluctuate on a circadian cycle. Two key plant hormones, auxin and potassium, are involved.
| Hormone | Role in Leaf Curling |
|---|---|
| Auxin | Promotes cell elongation which causes leaves to become flat |
| Potassium | Promotes cell contraction which causes leaves to curl |
At night, decreasing levels of auxin and increasing levels of potassium cause the leaves to curl upward. During the day, the reverse happens and auxin increases to flatten the leaves while potassium decreases.
The Role of Nastic Movements
In addition to plant hormone changes, prayer plants curl their leaves through nastic movements. Nastic movements are rapid plant movements that occur due to reversible changes in cell turgor pressure. Specialized bulliform cells on the undersides of prayer plant leaves gain and lose turgor pressure rapidly, facilitating these nastic movements that allow the leaves to curl and uncurl.
Factors That Influence Curling
While circadian rhythms cue most of the curling behavior in prayer plants, certain environmental factors can influence the degree of curling as well.
Light Exposure
Insufficient light exposure during the day can inhibit prayer plants from fully unfurling their leaves flat. Make sure prayer plants get adequate bright, indirect light during their waking hours to power photosynthesis and growth.
Temperature
Extreme cold or heat can cause excessive curling in prayer plants as the leaves attempt to protect themselves by exposing less surface area. Keep prayer plants at a comfortable room temperature between 60-80°F during the day and around 60°F at night.
Watering
Underwatering can cause prayer plant leaves to shrivel and curl inward as the plant tries to prevent water loss. Overwatering can also inhibit prayer plants from unfurling fully. Maintain evenly moist soil, watering when the top several inches become dry. Well draining soil and avoiding standing water promotes healthy opening and closing of the leaves.
Humidity
Prayer plants prefer very high humidity. In dry indoor air, the leaf edges may brown and curl under as the plant struggles to contain water loss. Use a humidifier or place prayer plants on pebble trays to boost moisture in the air. Grouping plants together also creates a little more humidity. Misting prayer plants can help as well.
Pests & Diseases
Prayer plant leaves can curl from pest or disease problems like fungus, bacteria, mites, or aphids. Inspect plants regularly and treat any issues immediately to avoid excessive curling of the foliage.
Age
As prayer plants mature and leaves age, they may not curl up as tightly at night. However, younger leaves will continue to show the characteristic movement. Older prayer plant leaves may also yellow or brown. Trim off aged foliage to encourage new growth.
Tips for Healthy Curling Behavior
Here are some tips to promote healthy curling behavior in prayer plants:
– Provide bright, indirect sunlight during the day.
– Use grow lights if natural light is insufficient.
– Water thoroughly when soil is partly dry and ensure adequate drainage.
– Mist leaves or use a humidifier to create 60-70% relative humidity.
– Keep room temperatures between 60-80°F and avoid cold drafts.
– Apply a balanced liquid fertilizer monthly during growing season.
– Avoid repotting unnecessarily which can disrupt curling rhythms.
– Prune off old leaves and stems to encourage new growth.
– Monitor for pests or diseases and treat promptly.
– Rotate plants periodically so all sides get light exposure.
With proper care simulating their natural tropical habitat, prayer plants will continue their unique practice of raising and lowering their leaves day and night. It’s this special behavior that makes them such a charming houseplant.
Common Prayer Plant Species & Their Curling Behaviors
There are around 50 species of prayer plants. Here are some of the most common types and details on their leaf curling habits:
Maranta leuconeura kerchoveana (Rabbit Tracks)
– Leaf undersides have light purple spots resembling rabbit tracks.
– Leaves curl completely upward at night, unfolding flat during the day.
– 10-12 inches tall and wide with oval shaped leaves 4 inches long.
Maranta leuconeura erythroneura (Red Prayer Plant)
– Olive green leaves with red veining.
– Leaves fold upright at night.
– Grows 6-10 inches high and wide. Leaves reach 3-4 inches long.
Calathea zebrina (Zebra Plant)
– Leaves have dark green stripes on top and purple underneath.
– Leaves curl vertically at night.
– Reaches 1-2 feet tall. Leaves grow to 9 inches long and 3 inches wide.
Calathea makoyana (Peacock Plant)
– Leaves have purple spots that resemble a peacock’s tail.
– Leaves lift upward at night and point toward the sky.
– Grows 12-15 inches high with leaves 8-10 inches long and 4 inches wide.
Ctenanthe lubbersiana (Golden Fishbone Prayer Plant)
– Olive green leaves with golden stripes that resemble fish bones.
– Leaves fold upright at night.
– Grows about 1 foot high and wide. Leaves reach 5 inches long.
Maranta leuconeura
– Oval-shaped leaves have dark green and light green splotchy patterns.
– Foliage curls into upright position at night.
– Reaches about 1 foot tall and wide. Leaves are 3-5 inches long.
Calathea ornata (Pinstripe Plant)
– Leaves have pink striping over green.
– Leaves curl vertically at night.
– Grows to 2 feet high with leaves 1 foot long and 4 inches wide.
While prayer plant species have slightly different leaf shapes, markings, and sizes, they all share the defining trait of raising their leaves upright at night. Their unique nyctinastic curling sets them apart from other houseplants. With proper care, prayer plants will exhibit their signature circadian curling behavior on a daily basis.
Frequently Asked Questions
Why are my prayer plant’s leaves not curling up at night?
If your prayer plant’s leaves remain flat at night, it likely isn’t getting the right day/night conditions to trigger leaf curling. Be sure it gets adequate sunlight during the day. Cooler nighttime temperatures around 60°F will encourage curling. Other issues like overwatering, dry air, or pest problems can inhibit curling so check these factors.
Why is my prayer plant curling its leaves during the day?
Prayer plants that curl their leaves during the day are showing signs of stress. This could be from too little light, dehydration, or temperatures that are too cold. Try moving the plant to a brighter location, watering more frequently, or warming the surrounding air to see if leaves return to normal unfurling during the day.
What should I do if the leaf edges are brown and curled under?
Brown, shriveled leaf edges indicate the prayer plant is not getting enough humidity. Up the humidity level around the plant by misting the leaves, using a pebble tray, or getting a humidifier. Keep the plant away from heating vents which can dry out the air.
Why are my prayer plant’s leaves curling too tightly?
If prayer plant leaves are curling into very tight upright coils, the plant is likely stressed. This could be from excessive light, overwatering, temperature extremes, or shock from repotting or moving locations. Adjust lighting, watering, temperature accordingly and avoid unnecessarily repotting.
Should I mist my prayer plant’s leaves?
Misting can help boost humidity around your prayer plant. But take care not to get water droplets on the actual leaves which can lead to fungal diseases. Instead, focus misting around the plant rather than directly on it. Use a humidifier for the best humidity increase.
Conclusion
Prayer plants exhibit specialized nyctinastic movement, curling their leaves upward at night and unfurling them during the day. This circadian rhythm behavior developed to conserve energy, protect the plants at night, and maximize photosynthesis in daylight. While influenced by light and plant hormones, certain factors like temperature, humidity, and care impact how vigorously prayer plants curl their leaves. With proper daytime light and darkness at night prayer plants will continue their unique dance as their leaves rise and fall with the sun each day.