Choosing the right soil mix is one of the most important—and often overlooked—parts of keeping indoor plants healthy. The right blend regulates moisture, stores nutrients, and creates the environment needed for optimal growth. Learning what soil your plants prefer could make the difference in whether your plant fails or thrives.
Sometimes All-Purpose Potting Soil Isn’t the Answer
Standard potting mix isn’t always the best option. Instead, understanding the environment where the plant naturally grows can guide you to a soil blend that mimics its native environment—giving it the best chance to flourish.
It Depends on the Plant
Broadly speaking, there are three main types of house plants: epiphytes, aroids, and cacti and succulents. Each has a specific soil need, so it’s important to properly identify your plant before potting it with soil.
Epiphytes: Air-Loving Plants
Epiphytes are plants that grow on other plants or surfaces in nature. They absorb water and nutrients from the air, rain, and debris around them.
Popular examples include orchids, staghorn ferns, and some species of Christmas cactus.
These plants prefer a chunky, airy mix that allows roots to breathe, such as orchid bark, moss, perlite, and coconut husks. These lightweight materials create air pockets that prevent root rot while retaining sufficient moisture.
These plants do best when fertilizer is applied directly to the material the plant is growing in, rather than diluting it in water and soaking the entire pot, as you would do with most plants. A slow-release fertilizer or a concentrated fertilizer directly onto the soil mix works better than being constantly surrounded by nutrient-rich soil for epiphytes.
For a soil-free option, some people opt for LECA (Lightweight Expanded Clay Aggregate) balls that mimic the airy, moisture-balanced environment epiphytes have in nature when they grow on trees or rocks. LECA balls are inert and contain no nutrients at all, unlike a soil medium that holds some nutrients from organic matter. Plants grown in LECA need to receive all their nutrients from a nutrient solution made from fertilizer diluted into water. A nutrient solution can be added to a reservoir to create a semi-hydroponic system.
Aroids: Tropical Foliage Favorites
Aroids are tropical, leafy plants that can be identified by their floral structure; a cluster of tiny flowers that create a spike surrounded by a petal-like sheath. Some common examples include peace lilies, pothos, and monsteras.
Most aroids in the wild are found in tropical forests floors or climbing plants that attach themselves to trees. Environments that are humid with soil made up of lots of decaying organic matter. Aroids thrive in rich, moisture-retentive soil that still allows good airflow to the roots.
An ideal aroid soil mix would include lots of organic matter like worm castings, compost, and coco coir. And chunky materials for drainage and aeration like orchid bark, perlite, and charcoal. A small amount of traditional potting soil would also be good in the mix.
Unlike epiphytes, aroids like water-diluted fertilizer to deliver nutrients evenly throughout the soil.
Succulents and Cacti: Masters of Water Storage
Cacti and succulents are both adapted to survive in dry, low-moisture environments, but they’re not exactly the same. While all cacti are succulents, not all succulents are cacti.
Cacti, such as prickly pear and agave, often grow in rocky, sandy soils with little organic matter. The environments they are found in get infrequent rain but when it does it’s often heavy, so cacti roots have adapted to take up water quickly and then dry up and go dormant during dry periods. Cacti store water in their thick, succulent stems, reducing the need for constant water absorption from the roots.
Soil needs for a cactus include an extremely fast-draining mixture to prevent root rot. A high ratio of inorganic materials like coarse sand, pumice, and clay. A minimal portion of organic matter, just enough to provide some nutrients and anchor the roots.
Succulents, such as aloe and jades, also grow in dry climates but some are found with higher humidity and rainfall.
Succulents require similar soil to cacti. They also need a fast-draining mixture with similar materials but can hold slightly more moisture than cactus soil. They prefer slightly more organic matter in their mixture, more potting soil, compost, etc.
If purchasing a bag of combination cactus and succulent soil mix, a desert cactus will most likely need more inorganic materials added to the mix, such as extra pumice, perlite, or coarse sand. This will ensure the soil won’t hold too much moisture and cause root rot for the cacti.
Cacti and succulents like a small amount of diluted, water-based fertilizer during the growing season. Avoid fertilizing during winter dormancy.
Soil is Only Half the Battle
Figuring out the soil is only half the battle. You still need to figure out the lighting to ensure your house plants get adequate sunlight. Once you figure out lighting and soil, you’re well on your way to growing a happy, healthy plant.
Resources
- Plants and products provided by Weston Nurseries
- Epiphytes (orchid, staghorn fern, Christmas cactus)
- Complete Soil Mix = Sol Soils – Orchid Chunky Mix
- Fertilizer = ready-to-use Orchid Plant Food
- Other soil option = Leca balls
- Aroids (peace lily, monstera, pothos, ZZ plant)
- Complete Soil Mix = Sol Soils – Houseplant Mix
- Aroids like a chunky, airy soil. There are various ways to create an aroid soil mix but here is one:
- 40% Coco Coir
- 35% Bark
- 20% Perlite
- 5% Charcoal
- 5% Worm Castings
- Smart-release fertilizer = Osmocote Outdoor & Indoor
- Liquid fertilizer = Schultz Plant Food Plus
- Cacti (prickly pear, agave, blue barrel cactus) and Succulents (jade, aloe, hens & chicks)
- While they require similar soil mixes, cactus soil should have less organic matter and be faster draining than succulent soil.
- Complete Cactus Soil Mix = Sol Soils – Cactus gritty mix
- Complete Succulent Soil Mix = Sol Soil – Succulent mix
- Fertilizer = Schultz – Cactus liquid plant food
