Fast-Draining Soil for Succulents

Potted Specimens - Fast Draining Soil for Succulents
This succulent collection features inspiring examples of plant and pot compositions

“Water applied must drain through the soil in fifteen seconds. If it fails to do so, the soil is too dense.” Such advice came to me decades ago from an old school nurseryman who specialized in cacti and succulents. Back then I thought this fifteen second law regarding fast-draining soil for succulents was ridiculous. After moving to the desert I learned what native cactus ground looks like. Water applied instantly vanishes into the soil. The nurseryman was right.

Today about half my collection of succulent plants are grown in small pots that come into an unheated south facing greenhouse for the winter. They are planted in Black Gold Cactus Mix, which drains within the fifteen second rule.

Soil is Everything

What many new succulent gardeners fail to understand is that, because cacti root differently, soil is everything. Standard plants go deep to catch ground moisture after the surface soil dries out. In the desert, cacti adapt to short periods of rainfall by spreading out shallow roots over a large area. These roots are capable of rapidly taking up water before it water drains through porous ground. This water is immediately stored in a succulent’s specialized tissues that hold it between widely spaced rain events. Shallow rooting is the reason why most cacti do best in low, wide pots, pans and bowls with large, open drain holes.

Succulent Pot - Fast Draining Soil for Succulents
This low, wide pot allows for plenty of surface root development beneath the surface gravel.

Cactus potting soil contains perlite, which looks like little white pieces of popcorn. While it is excellent for a root zone, it floats to the surface when I water. This and little bits of organic matter become entangled in the spines or settle in nooks and crannies of smooth surface skin. This is not only unsightly, it brings soil born bacteria in direct contact with the plant skin which may begin the rotting process.

To control these floaters, succulent aficionados apply a layer of fine gravel on top of the potting soil to keep it all in place when water is applied. White rock is popular for modern style containers with a more graphic look. I prefer washed gravel because it’s more naturalistic and blends with the rocks I find on walks to use as an accent stone. You can also use aquarium gravel for more unusual or brightly colored composition of succulent, pot and surface material.

Transplant Gently

Even the smallest damage to the skin of a plant can allow pathogens to enter and begin the process of internal cell damage which leads to softening rot. When transplanting cacti, I handle each plant carefully to avoid the slightest damage. Once removed from the original pot, I do not replant immediately but allow it to sit bare root in the open air for a few days. This lets any damaged roots or skin heal over or callus before repotting in new soil. Failing to do so brings soil pathogens into direct contact with a wound, which inevitably infects internal tissues.

When your soil is sufficiently well drained for cacti and gorgeous succulents, it becomes downright difficult to over water them. The warmer months of summer are their rapid growing season. During this growing season, water often, feed modestly, and above all, make sure you use Black Gold Cactus Mix to be sure it drains in about fifteen seconds.

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.

Leave a Reply

Content Disclaimer:

This site may contain content (including images and articles) as well as advice, opinions and statements presented by third parties. Sun Gro does not review these materials for accuracy or reliability and does not endorse the advice, opinions, or statements that may be contained in them. Sun Gro also does not review the materials to determine if they infringe the copyright or other rights of others. These materials are available only for informational purposes and are presented “as is” without warranty of any kind, express or implied, including without limitation warranties of merchantability, fitness for a particular purpose, and non-infringement. Reliance upon any such opinion, advice, statement or other information is at your own risk. In no event shall Sun Gro Horticulture Distribution, Inc. or any of its affiliates be liable to you for any inaccuracy, error, omission, fact, infringement and the like, resulting from your use of these materials, regardless of cause, or for any damages resulting there from.