Stop Succulent Sudden Meltdown

baby toes
Babytoes, another living stone, blooms like lithops in late winter indoors on a bright windowsill.

There are few growing experiences as disappointing as meltdown.  When your favorite indoor cacti or succulents get soft for no reason at all, it’s downright frustrating.  The phenomenon of succulent sudden meltdown is caused by an infection that enters the internal tissues and causes rot.  Like tooth decay, rot works its way throughout the interior of the plant before you ever know it’s there.  While a tooth eventually tells us through pain that there’s a problem, most gardeners never really know what killed their plant.  Nine times out of ten it’s moisture related because gardeners tend to overwater and microbes plentiful in home growing conditions aren’t naturally as numerous in the arid environments where these plants originate. Succulents lack the needed defenses to ward off rot.

A pot lithops with pebbles that match to show its unique ability to blend into gravel for protection.
A pot lithops with pebbles that match to show its unique ability to blend into gravel for protection.

Some succulents are even more susceptible than others. Living stones such as lithops are notorious for sudden meltdown.  They’re frustrating because  these unique tiny succulents so darned interesting, yet they are so hard to grow.

Lithops and their ilk are called living-stones because they are stone-like in appearance. They evolved in the dry Namibian Desert where there’s a long dry season and lots of plant-eating wildlife.  Succulents are most attractive to animals because they store lots of water, so they are predated upon to slake thirst.  While other succulents have sharp armor to protect themselves from browsers, living stones survive through the art of camouflage.

Animals can’t pick these rock-like succulents out of a dry stony riverbed or desert floor.  The gravel and sand habitat has very little fertility and almost no water-holding capacity.  When the brief rainy season rolls around, these plants are fertilized by nitrogen-rich organic matter that has accumulated on the desert’s surface, but little remains in the sandy soil.  Roots rapidly absorb what nutrition they need, then flower and finally hunker down for the rest of the year.  Much of the time their roots lie desiccated on the highly porous ground, waiting for the moisture to return.

A single large lithops in a handmade pot makes a beautiful holiday gift or accent for your office.
A single large lithops in a handmade pot makes a beautiful holiday gift or accent for your office.

Now that you know where living stones like to grow in the wild, it’s easy to see why using washed gravel or white rock is so useful when potting them.  Think of the needed soil conditions for these plants as a sandwich composed of three layers.  First, apply a layer of gravel on the bottom of the pot to about a third of its overall depth.  Place the living stone and its rootball on top of the gravel and surround it with it with Black Gold Cactus Mix potting soil.  Try to keep Cactus Mix beneath the green part of the plant so there’s little direct contact between plant tissues and microbe-rich organic matter.  Finally, use more gravel or sand for the top layer to nest the living stone in pebbles that match (white or natural), just as they grow in the wild.

This planting method can be used for most other cacti and succulents too, especially if you’ve had trouble in the past with rotting plants.  A super porous approach makes it nearly impossible to overwater, particularly in the winter when plants aren’t growing.

BG Cactus Mix frontIf you live in a humid climate or where there is summer rain, use this three layer sandwich with equal proportions to pot any sized cactus or succulent.  This solves the primary problem that leads to meltdown: too much moisture and organic matter at the root zone.  When you do apply water, it penetrates quickly and exits just as fast.  That narrow layer in the center retains just enough for hydration, then the top and bottom layers allow enough air penetration to quickly dry things out again.

About Maureen Gilmer

Maureen Gilmer is celebrating her 40th year in California horticulture and photojournalism as the most widely published professional in the state. She is the author of 21 books on gardening, design and the environment, is a widely published photographer, and syndicated with Tribune Content Agency. She is the weekly horticultural columnist for the Desert Sun newspaper in Palm Springs and contributes to Desert Magazine, specializing on arid zone plants and practices for a changing climate. She works and lives in the remote high desert for firsthand observations of native species. Her latest book is The Colorful Dry Garden published by Sasquatch Books. When not writing or photographing she is out exploring the desert on her Arabian horse. She lives in Morongo Valley with her husband Jim and two rescue pit bulls. When not writing or photographing she is usually out riding her quarter horse.

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