Light
Aim for bright, indirect light. On the University of Illinois Extension scale, that is high light of about 300 foot-candles, found directly in front of an east or west window or within five feet of a south one. NC State describes its natural light as dappled, shade filtered through an upper canopy, which is a good picture of what to copy indoors: plenty of brightness, little raw sun on the leaves.
Light shows up quickly in the spacing of the leaves. NC State notes that large gaps between leaves mean the plant is not getting enough light, and those bare sections never fill in later. Too much sun has the opposite effect, scorching the leaves. A sheer curtain on a sunny south or west window, or a hook a few feet back from the glass, usually solves both problems at once.
| Range | Medium light to bright light, best in bright light |
|---|---|
| Foot-candles | 150 to 300 fc (1,615 to 3,229 lux) |
| Windows | East, West, South · no direct sun |
| Sources | North Carolina Extension Gardener Plant Toolbox; University of Illinois Extension |
Water
Water thoroughly, then wait until the mix has dried out completely, which is the rule NC State gives. The buried tuber works like a small reservoir, so the plant handles a dry pot far better than a wet one. When you do water, soak the mix until it drains from the bottom and empty the saucer, so the tuber never sits in standing water.
Learn the two warning signs. Yellowing leaves and soft, failing stems point to overwatering and root rot. Limp, wilted leaves on light, dry mix point to underwatering, and they recover within a day or two of a good drink. Water at the soil rather than through the hanging vines, which tangle and hold moisture around the leaf joints.
In winter the plant goes dormant, and NC State advises reducing water even further. Growth all but stops, the mix dries slowly, and a summer routine kept through December is the most common way these plants are lost. Water just enough that the leaves stay firm.
| Rule | When the mix is dry all the way down: let the potting mix dry out completely between waterings |
|---|---|
| Winter | The plant is dormant over winter, and NC State advises cutting watering back even further than in summer. |
| Watch for | Overwatering rots the tuber and yellows the leaves, the problem NC State warns about first. |
| Wilted, limp leaves on dry mix are the sign of underwatering. | |
| The underground tuber stores water, so a short dry spell does far less harm than a wet pot. | |
| Sources | North Carolina Extension Gardener Plant Toolbox |
Soil and pH
NC State recommends a well-drained, sandy potting soil. A cactus and succulent mix works, or a regular houseplant mix with a generous share of coarse sand or perlite stirred in. Avoid dense, peat-heavy mixes that stay damp around the tuber. Plant the tuber at the same depth it grew before, with its top near the surface, and use a pot with a drainage hole; a shallow, wide container drains faster than a deep one.
| Mix | A well-drained, sandy potting mix, such as cactus mix or houseplant mix opened up with coarse sand or perlite. |
|---|---|
| Ingredients | cactus and succulent potting mix, coarse sand, perlite |
| Sources | North Carolina Extension Gardener Plant Toolbox |
Humidity
None of the sources we read sets a humidity level for this plant. As a succulent from dry southern African hillsides, it grows well in ordinary room air, including the dry air of heated homes in winter, which the University of Illinois Extension puts at under 30 percent in most houses. There is no need to mist, and wet leaves in a cool room only invite rot.
Temperature
We found no published minimum temperature specific to string of hearts indoors. NC State says it can be planted outside in USDA zone 10, where it is frost free, but that is a garden rating, not a houseplant target. For indoor care, follow the University of Illinois Extension guidance for houseplants in general: days of 65 to 75°F (18 to 24°C) with nights 5 to 10 degrees cooler, which means keeping it above about 55°F (13°C). Keep it out of cold drafts and off frosty glass.
| Minimum | 55°F (13°C) |
|---|---|
| Humidity | Average room humidity. No source we read gives a humidity need; this hillside succulent grows in ordinary room air without misting. |
| Sources | University of Illinois Extension; North Carolina Extension Gardener Plant Toolbox |
Fertilizer
Feed lightly. The sources give no feeding schedule for this species, so use the University of Illinois Extension rule for houseplants: no more than once every one to three months from March to September, with a balanced or 1:2:1 houseplant fertilizer at label strength or weaker. Stop during the winter dormancy, when unused fertilizer only builds up salts in a pot that is rarely flushed.
| When | March to September, while the vines are growing, every 4 to 13 weeks, none in winter |
|---|---|
| What | Houseplant fertilizer, balanced (10-10-10) or 1:2:1, at the label rate and never stronger, label rate |
| Sources | University of Illinois Extension |
Work out the dose for your watering can with the fertilizer dilution calculator →
Repotting
NC State says this plant likes to be crowded and that repotting should be put off until it is truly necessary. That suits the tuber, which rots in a large volume of wet mix. Move it up only when tubers crowd the surface, water runs straight through a pot packed with roots, or the old mix has broken down into something that stays wet.
Do it in spring or early summer, when the University of Illinois Extension says plants repot best because they are actively growing. Untangle the vines first or lay them over your arm, choose a pot only an inch or two wider, and replant at the same depth in fresh sandy mix. Firm the mix gently around the tuber and water once to settle it, then let it dry out completely as usual.
- Tubers crowd the surface and push against the rim
- Water runs straight through a pot packed with roots
- The mix has broken down and stays wet