Soil & potting mix
Best soil for String of dolphins (Senecio peregrinus)
Also called dolphin plant, flying dolphins.
About String of dolphins
Senecio peregrinus · also called dolphin plant, flying dolphins · houseplant
String of dolphins is a quirky succulent hybrid with leaves shaped like leaping dolphins. A cross between string of pearls and Senecio articulatus. Mildly toxic to pets like its parents and demands bright light to keep its distinctive leaf shape.
Curio x peregrinus (Senecio x peregrinus), not a wild species but an intergeneric hybrid of Curio rowleyanus (string of pearls) and a Curio articulatus relative; the leaves curve into two small points resembling leaping dolphins.
Requires a gritty, fast-draining succulent or cactus mix; the fleshy dolphin leaves store water, so the roots must never sit wet.
Preferred mix: Free-draining succulent mix
Watch for — Mushy stems: Overwatering; reduce frequency and improve drainage.
Sources: en.wikipedia.org, plants.ces.ncsu.edu
Why string of dolphins needs this mix
String of dolphins stores water in its leaves and stems, so it wants a free-draining, gritty mix that dries out fully between waterings — not a moisture-holding one.
- String of dolphins carries its own water supply in its thick tissue, so the soil's job is to drain fast and then get out of the way.
- Its roots are adapted to short wet spells followed by long dry ones — a mix that stays damp removes the dry phase they depend on.
- A gritty mix also keeps the plant compact and well-coloured rather than soft, leggy and prone to collapse.
For the full picture on what makes up a good mix, see our guide to the main types of soil and potting media — it explains why each ingredient above behaves the way it does.
What goes wrong with the wrong mix
The wrong soil is one of the most common reasons string of dolphins struggles, and the damage often shows up weeks later as a watering problem. For this species specifically:
- Standard potting compost on its own stays wet far too long for string of dolphins; the lower leaves and stem base go soft and translucent first.
- Big plastic pots full of dense mix hold a wet core long after the surface looks dry — that hidden wet zone is where rot starts.
- Anything sold as "moisture control" is the opposite of what this plant wants.
Treating string of dolphins like a leafy houseplant and using plain compost. It needs at least half its volume as grit, perlite or pumice to survive long term.
pH — does it matter for string of dolphins?
pH is not a concern for string of dolphins — anything from mildly acidic to neutral (6.0-7.0) works. Get the drainage right and pH looks after itself.
If you want to check or adjust it, the soil pH guide walks through testing and the safe ways to nudge a mix more acidic or more alkaline.
DIY mix vs a bagged one
A good bagged "cactus and succulent" mix works for string of dolphins if you add roughly 30-50% extra perlite or grit. Mixing your own from the ratio above gives you full control of how fast it dries.
Drainage and the pot
Use a pot with a drainage hole and empty the saucer within minutes of watering. Terracotta is more forgiving than glazed or plastic because it dries the rootball faster.
This mix decomposes slowly, so string of dolphins only needs repotting every 2-3 years — mainly to refresh the grit and check the roots are firm and pale. When the time comes, our repotting guide for string of dolphins covers the timing and technique step by step.
String of dolphins soil — frequently asked questions
What is the best soil mix for string of dolphins?
2 parts standard cactus or succulent compost : 1 part perlite or pumice : 1 part coarse grit or coarse sand. String of dolphins carries its own water supply in its thick tissue, so the soil's job is to drain fast and then get out of the way.
Can I use normal potting soil for string of dolphins?
Standard potting compost on its own stays wet far too long for string of dolphins; the lower leaves and stem base go soft and translucent first. A good bagged "cactus and succulent" mix works for string of dolphins if you add roughly 30-50% extra perlite or grit. Mixing your own from the ratio above gives you full control of how fast it dries.
Does string of dolphins need a special pH?
pH is not a concern for string of dolphins — anything from mildly acidic to neutral (6.0-7.0) works. Get the drainage right and pH looks after itself.
Should I buy a bagged mix or make my own for string of dolphins?
A good bagged "cactus and succulent" mix works for string of dolphins if you add roughly 30-50% extra perlite or grit. Mixing your own from the ratio above gives you full control of how fast it dries.
How often should I refresh the soil for string of dolphins?
This mix decomposes slowly, so string of dolphins only needs repotting every 2-3 years — mainly to refresh the grit and check the roots are firm and pale. Use a pot with a drainage hole and empty the saucer within minutes of watering. Terracotta is more forgiving than glazed or plastic because it dries the rootball faster.
Keep reading
- String of dolphins care — the full brief (light, water, humidity, problems, pet safety)
- How often to water string of dolphins — the schedule the mix feeds into
- Repotting string of dolphins — when and how to refresh the mix
- Soil pH guide — test it and adjust it safely
- How often to water succulents — the soak-and-dry method
- Overwatered plant — signs and recovery
- Root rot — how the wrong soil starts it, and how to save the plant
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- All 200 soil and potting-mix guides in the Growli library