Container and Growing Medium Guide

Containers and Growing Media

A Detailed Guide

Written by Miles Ridgway - Henry's Haworthia (owner)

When it comes to growing media for Haworthia collectors, it seems that every expert has a different blend to recommend. Our own experience has shown that Haworthia plants are highly adaptable and will thrive in virtually any kind of soil or gritty mix, given proper care. The most important part is not the medium or container itself, but rather that you, as the caretaker, carefully choose what works best for you, your climate, and your watering habits! 

The purpose of this guide is not to go into detail about each medium (there are plenty of other online resources that do this) or prescribe one as being better than another, but rather to briefly discuss their properties and how they relate to various environmental conditions.

Growing Media Types

The most important factor to consider when choosing a growing medium is water retention. Every ingredient behaves slightly differently. Below, there is a list of common soil ingredients and roughly where they fall as far as water retention.

Nonporous grit (low water retention)

• Perlite
• Chicken grit (granite chips)
• Decomposed granite
• Sand
• Gravel

Porous grit (medium water retention)

• Pumice
• Akadama
• Calcined clay (Turface)
• Lava rock (scoria)
• Pine bark fines (organic, but behaves as porous grit)
• Calcined diatomaceous earth
• Zeolite

Organic material (high water retention)

• Succulent soils
• Raised bed mixes
• Compost
• Coconut Coir

Organic material (very high water retention)

• Peat
• Potting soil

Mixing ingredients will, as you could imagine, give you a medium that lies somewhere between the water retention of each ingredient. Keep in mind that some ingredients also supply nutrients (potting soils, succulent mixes, raised bed mixes, etc.), while others do not (non-organics, peat, coir). If you are using a 100% inorganic gritty mix, you must supply nutrients with every deep watering, which can make it easy to overfertilize your plants if you are not careful. pH must also be taken into consideration, with the outliers being peat (very acidic) and calcined diatomaceous earth (alkaline). The other ingredients are roughly within the acceptable pH range of 6~7.

Factors that influence plants' water needs

You will see the best results when the growing medium is chosen to be most appropriate for your climate and care regimen. Before choosing a growing medium, we recommend that you carefully consider the following environmental conditions:

Increases water need

• High temperature
• Low humidity
• Lots of direct sunlight
• Windy conditions
• Small container size
• Porous containers (unglazed terracotta)

Decreases water need

• Low temperature
• High humidity
• Lower light conditions
• Stagnant air
• Large container size
• Nonporous containers (glazed, or plastic)

Factor these environmental conditions against your own care habits, or rather, how you want to care for your Haworthia plant. For example, if you find that you forget to water your plants for weeks or simply do not want to have to worry about babying a plant, use a highly water-retentive growing medium and then water accordingly for that medium. If you are prone to over-watering or find it difficult to maintain the proper moisture level for succulents, use a non-porous grit or mixture of grits with the understanding that you will have to water the plant frequently, at least every week or multiple times per week in hot summer conditions.

For beginners, we recommend a mix of 50/50% potting soil and perlite (many gardeners already have these ingredients on hand). It is a good starting point and reduces the danger of overwatering compared to plain potting soil or plain succulent soil. 100% pumice or 100% calcined clay are also great beginner grit mediums. 

Choosing the right container

You can grow Haworthia plants in almost any container that you want, provided that you care for it properly and that it has drainage holes. In addition, putting rocks at the bottom of the pot for "drainage" is counterproductive.

Graphic explanation of perched water table in container plants. Drainage rocks do not work!
Image credit: https://deepgreenpermaculture.com

We recommend a container that allows for the soil to be at least 4" deep. Many Haworthia varieties grow long, tuberous, contractile roots that become cramped and can be prone to rotting in smaller containers. We also recommend that your container be only slightly wider than the spread of the leaves. It is okay to give your Haworthia growing room, but keep in mind that overpotting the plant will decrease its water needs drastically and may make it more difficult to maintain the proper moisture level.

Graphic explanation of one reason we recommend deeper pots for haworthias
Image credit: J. Musser

Consider also that some containers are porous (unglazed terracotta) and some are not. Porous containers will allow the soil to dry much more quickly than nonporous containers.

We have found that there is no single "best" growing medium. If you are like us, you will likely try many different kinds over the years. We hope that this guide has helped you to think about what media you do and do not want to try!

Works cited:

• www.haworthia.com
• www.gardening.stackexchange.com
•  www.deepgreenpermaculture.com
• Our experience

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