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What you add to yours depends on the plant you’re growing. Nearly all species will thrive better when there’s adequate drainage and the ability for the roots to have some level of air exchange. This is true whether it’s a cactus, succulent, or tropical plant.

In recent years, I’ve come to rely on a pretty consistent blend of organic and inorganic materials, swapping the ratios around to suit my needs for the growth habits of the plants.

My baseline cactus/succulent blend is:

50% pumice
25% orchid bark
25% cactus soil

My baseline tropical or houseplant soil blend is:

50% tropical soil
25% pumice
25% orchid bark

I’ll link to specific brands that I like best below, including brands that Amazon should carry, or what I’ve been able to find locally.

Drainage and Aeration

Drainage can also be associated with aeration around the roots. No matter the species, all plants need some level of air around their roots. There’s few, if any, species that thrive in completely stagnant soil.

To combat this, mix in a generous amount of pumice or similar inorganic medium into your soil to assist in creating air pockets and variation in soil particle size. This also ensures adequate drainage, which prevents rot, mold, and other problems.

Organic Material

Even plants growing in rocky soils need food! While cacti and succulents can thrive in a highly inorganic mix, even 100% inorganic, they still need nutrition to grow. For the fully inorganic mix, that’s provided through fertilizer – but if you’re new to cacti, this is often far less forgiving of mistakes than if you have at least 25% organic material in there.

For houseplants, tropicals, or just species that prefer more moisture around their roots for longer than a day, increasing your organic matter ratio accordingly is helpful. I use a gritty, chunky mix for my cacti and succulents, and a finer mix full of worm castings, guano, and other nutrient-rich bits that makes my house plants happy.

Pot Shape and Material

Ideally, pots should be wider at the top than the bottom. This decreases the “saturated zone” at the bottom of your soil where the water takes the longest to be absorbed or vaporate away, and also decreases risk of rot and mold.

Terra cotta pots are ideal for your cacti and succulents, as they help keep roots cool with how thick they are and slow to heat, as well as assist in water evaporation. For your indoor tropicals, plastic might work best! It’s light, often drains quickly, and doesn’t evaporate too fast – which can be an issue depending on the species.

Soil Brands and Types

Some of these can be purchased online, some must be found locally.

Cacti and Succulent

E.B. Stone

Cactus-specific mix

Tropical / House Plants

Fox Farms / Happy Frog Soil

You can use Miracle-gro or similar, but plan to amend heavily.

Cactus Soil Amendments

Pumice

Lava Rock (any color, really)

Play sand

Decomposed granite (preferably sifted) – if ordering online, get this instead

Orchid bark

Tropical / House Plant Soil Amendments

Drainage and soil structure only; for fertilizers, check the blog for more in-depth posts.

Pumice

Orchid Bark

Horticultural charcoal

Perlite

Vermiculite

Coconut husk – coir, fiber, or “peat”

Sphagnum moss

Water

Water is what plants crave

You have to offer the right amount at the right time, but not overdo it.

You also need adequate drainage in your pots to ensure the water can flow out and not sit at the bottom of the pot, turning into swamp water.

I won’t go into details of rooting plants in water here; that’s a different topic than maintaining potted plants or in-ground plantings of cacti and succulents. Drainage is one of the most critical parts when it comes to watering your plants!

How much you water and how often you water will be highly impacted by the soil you use, and is a major reason I recommend creating your own blended soil for your plants. You can give them better draining soil or faster drying soil to help counter some of the challenges of your growing conditions.

Humidity is a major factor to consider when it comes to watering. High ambient humidity is great for tropical plants, and they consume less water trying to ‘breathe’ than they do in lower humidity conditions. Cacti, on the other hand, easily rot if they’re watered too much when the humidity is also high.

How much water?

In ideal conditions, potted plants should be thoroughly drenched until the water runs out of the bottom of their pot (yes, including cacti, succulents, and mesembs). This gives them the moisture needed to grow, yes, but your aim should be to evenly saturate their soil. This keeps dry pockets and related root death from occuring, and encourages consistent root development throughout the pot.

In addition, the flush of water through the pot rinses out any minerals or deposits that build up in the soil. If you’re using fertilizer or tap water, this is pretty critical to prevent harmful buildup of salts that’ll eventually kill your plant.

For in-ground plants, you should water as much as is needed to saturate the ground around them at least 1 – 2″ down. Use a stick or your finger to poke the soil and test that you’re saturating as much as you need. In very hot climates or compacted soil, it may take more water than you think.

How often should you water?

Entirely dependent on species and conditions. Cacti and succulents grown indoors, where for them, conditions are quite mild, need far less water than those outside. Tropicals, on the other hand, lose a lot of moisture and prefer more humid conditions, and may need much more water.

What about humidity?

Household humidity when climate control (heat or AC) is on is usually low enough for cacti and succulents to be content. Your tropical plants, however, may need a humidifier or dedicated grow case. I cart my tropical plants into the shower on a regular basis for a deep watering and high humidity session, but that’s a bandaid more than a holistic solution.

Fertilizing

Potted plants need food more often, and more consistently, than those in the ground. In-ground cacti and succulents almost never need fertilizer, as they’re able to get what they need from the soil around them. Tropical plants, depending on your area, may need supplementation to survive – but as I can’t grow any in the ground here, I can’t provide recommendations from experience.

Fertilizers recommended below are for potted plants.

Cacti and Succulent

Organic

Fish Emulsion: Use as often as you’d like during the growing season. Balanced, all-around food.

Worm Castings: Sprinkle on top of the soil in spring for plants that haven’t been repotted in 3+ years

Gypsum: Increases acidity of the soil while adding calcium; use very sparingly.

Vinegar: Alternative to Gypsum, use a small amount to acidify your water (helps with nutrient absorption). Use a pH meter to measure.

Non-Organic

Balanced Fertilizer: Use at half strength during the growing season.

Osmocote: Slow release pellet fertilizer; sprinkle on top of soil in spring

Tropical / House Plants

Organic

Fish Emulsion: Use as often as every watering, year-round.

Worm Castings: Add to the top of soil that’s more than 6 months old, or mix into your soil blend when potting plants up.

Bone Meal: Bulb type plants love having this added to their soil in spring; Alocasias and Colocasias in particular. Follow the directions on the package.

Non-Organic

Dyna-Gro Foliage Pro: My all-time favorite, I haven’t used anything else in the last 3 years. Mix with your water as recommended on the label, and use with every watering during spring and summer.

Osmocote: Slow release pellet fertilizer. Mix into the top of the soil every 6 to 12 weeks, as directed on the label.