String of hearts leaves can curl up if they are not watered often enough or watered too lightly causing the plant to deplete the moisture reserves in the leaves causing them to shrivel. Too much sun and strong air currents also dry out the leaves of a string of hearts plants with a thinner curled up appearance.
Sometimes when soil dries out, it can repel water off the surface which prevents the roots from accessing moisture and causes the leaves to curl.
Keep reading for the right potting soil to prevent string of hearts leaves curling and how to implement the solutions, so the plant can recover to a healthy appearance…
String of Hearts Leaves Curling Due to Drought Stress
String of hearts plants (Ceropegia woodii variegata) are succulents from Southern Africa that grow in hot and dry climates in gritty soils, with infrequent rainfall.
However, if string of hearts plants are not watered often enough, or watered too lightly then this can still cause the leaves to curl up and shrivel as a sign of drought stress.
String of hearts plants typically require watering once every 2 weeks with a generous soak.
It should be noted that whilst string of hearts does grow in a relatively dry environment, when it does rain it tends to be a deluge rather than light rainfall.
Therefore if you water too lightly then this only moistens the top inch or so of the soil and the water does not infiltrate and reach the roots.
The leaves should be rather plump when the plant is healthy as this is a survival strategy to store moisture in an environment in which rainfall can be infrequent.
A lack of water from not watering often enough or watering too lightly causes the leaves to turn thinner, shriveled and to curl as a sign of stress.
Fortunately, it is usually easy to revive your string of hearts with curling leaves with good watering practices.
How to Revive String of Hearts Curling up Leaves due to Underwatering
- Place your string of hearts plant in a basin of water for 10 minutes or so, to ensure that the soil can absorb the water after a period of drought.
- Allow the soil to dry out between bouts of watering (to avoid problems associated with overwatering such as root rot) before watering again.
- Give the string of hearts a generous soak of water each time, so that excess water trickles from the drainage holes in the base. This ensures that the water reaches the roots so they can uptake the moisture they require.
- Typically water your string of hearts once every 2 weeks in the Spring and Summer and once every 3 or 4 weeks in the Winter to replicate the moisture conditions of its native environment.
With two or three cycles of watering the string of hearts plant should show signs of recovery.
The key to watering string of hearts plants to avoid the leaves curling from drought but to also avoid the problems associated with over watering is to establish the correct watering schedule for your climate and the conditions in your home to ensure the plant stays healthy.
To establish how often to water string of hearts plants, give the soil a good soak, then monitor how long it takes for the soil at the bottom of the pot to dry out. To do that feel the soil through the drainage hole in the base of the pot.
If the soil feels damp then delay watering for a few days until the soil is dry. When the soil has just dried out, this is the perfect time to water with a good soak.
(For all the best watering practices read my article on how to water string of hearts).
Dry Soil can Prevent Water from Reaching the Roots
As string of hearts are drought-tolerant plants they prefer the soil to dry out between bouts of watering.
This can be a problem if the string of hearts is planted in a potting mix that contains peat as peat can turn hydrophobic (repels water) when it dries out completely.
Dry peat soil can cause water to run off the surface of the potting soil, and down the side of the pot or container, and out of the drainage holes.
This can give the appearance that the string of hearts plant is well watered but actually the water has not been absorbed properly into the soil and reached the roots of your plant which causes the leaves to curl as a sign of drought stress.
To revive a string of hearts plant with curling leaves, due to water-repellent soil the first step is to:
- Place the plant pot in a basin of water and let it soak for 10 minutes or so. Soaking the root ball properly can overcome the peat soil’s water-repelling properties as the water eventually soaks into the soil to reach the roots. This gives your string of hearts plant much-needed moisture so the curled-up leaves can start to recover from their drought stress.
- Even though the soil has been soaked, if there is peat the potting soil can bake hard again after drying up and you have the same problem. Whilst the soil is still moistened from the soaking of the root ball in the basin, loosen the soil around the root ball.
- Replace the soil with specially formulated succulent and cacti soil which retains a porous structure that allows water to infiltrate properly even if it has dried out. Succulent and cacti potting soil replicates the soil conditions of the string of hearts native environment, so that your string of hearts can be watered effectively and not suffer from root rot.
With good succulent and cacti soil, watering with a generous soak each time you water and watering once every 2 weeks or so, the curled up and dry shriveled leaves can recover from drought stress.
Too Much Sun Causes Leaves to Shrivel
String of hearts can handle some direct sunlight which can turn the leaves a shade of purple, but too much can cause the leaves to curl up and even scorch.
The best balance of sun for string of hearts plant is some morning sun followed by shade in the afternoon during the hottest part of the day or bright, indirect light when indoors.
Too much sun can contribute to the drying out of leaves as the plants struggle with the heat to draw up enough moisture as the soil dries out quickly and the leaves lose more water through transpiration.
Locate your string of hearts plant in an area of bright indirect light if the leaves have curled up so it does not have to contend with the stress of direct sunlight whilst it recovers.
Water the string of hearts plant with a good soak so that excess water trickles from the drainage holes in the base of the pot and wait for the soil to dry before watering again.
With 2 or 3 cycles of watering the string of hearts plant should show signs of recovery.
(If your leaves have a look scorched appearance or the plant looks unhealthy read my article how to revive a dying string of hearts plant).
Air Currents Dry the Leaves
Another contributing cause of string of hearts with curling leaves is too much air flow from wind, air conditioning, forced air, or convection currents from sources of heat when indoors.
String of hearts plants can grow well with some air flow but if the plant is in the direct air current of air conditioning, then the dry air can sap moisture from the leaves and dry out the potting soil quicker.
This results in the string of hearts plant depleting its store of moisture in the leaves which become thinner and curl up.
The solution is to simply locate your string of hearts in an area of the home with bright indirect light and out of the direct path of air currents that dry the leaves.
After 2 or 3 cycles of watering the string of hearts can begin to store water again in their leaves so they recover from being curled or shriveled.
(Read my article on how to care for string of hearts plants to ensure your plant stays healthy).
- String of hearts leaves curl up and turn thinner when not watered often enough or watered too lightly. String of hearts plants store moisture in their leaves so when the plant dries out the leaves shrivel and curl up as it uses its moisture reserves in the leaves.
- String of hearts leaves also dries up when in too much sun or in strong airflow which saps moisture from the leaves causing them to turn dry.
- Locate your string of hearts plant in an area of bright indirect light and out of the way of strong air currents from air conditions, wind, or forced air.
- Water the string of hearts with a generous soak, then allow the soil to dry out before watering again. The string of hearts plant with curled leaves can recover after 2 or 3 cycles of watering.