Can I Use Cacti Soil For Bonsai?


You can always find lots of ready-to-use potting mix for bonsai in garden centers, but they can be pretty expensive. You are thinking of any alternative medium that can equally cultivate healthy bonsai. How about a cacti mix?

Only small bonsai trees can successfully thrive in a cacti mix alone thanks to their 1) excellent drainage, 2) good absorption, 3) adequate aeration, and 4) nutrient content. However, cacti mix alone does not provide stable support to large bonsai trees due to its lightweight nature.

A lot of bonsai newbies are doubtful if the cactus mix is a viable substitute for bonsai trees. Is it really? Let’s figure it out.

What Is Cacti Soil?

Cacti potting mix or cacti soil is formulated particularly for growing and cultivating drought-tolerant plants such as cacti and other succulents. The suitable medium is designed to provide optimum drainage quality, aeration, and water retention.

Cacti soil contains no soil at all. Organic matters and inorganic aggregates are the constituents of a cacti medium. The ratio of components depends on the variety of the cactus, but the main point is to achieve a porous medium that drains well and provides excellent aeration for the roots. Cacti mixes contain a few organic compounds that readily supply moisture for the cacti.

Commonly used cacti mix components are pumice, lava or scoria rock, perlite, and sand aggregates. These inorganic compounds do not break down or expire. One or more of these inorganic compounds are blended with a small ratio of organic compounds such as composted pine bark, coco coir, or peat moss to aid moisture retention.

Is Cactus Soil Suitable for Bonsai Plants?

Cacti mix is as beneficial as bonsai soil when appropriately formulated. Looking closely at bonsai soil, it has the same texture and components as cacti soil. Bonsai mix is almost the same as cacti mix; therefore, cacti soil is the best alternative for bonsai soil.

As you might know, bonsai mix is expensive, especially if you have several bonsai trees to replant. This is because bonsai mix contains aggregates that are pricey and not readily available such as akadama. Hence, it is always wise to prepare your potting mixes using your particular recipe.

Cacti mix resembles bonsai soil because it contains almost the same components, which is why most bonsai keepers use it as a substitute substrate for their bonsai trees.

The trick with cacti mix is getting the right blend and mixing specific compounds such as akadama that match the requirements of your bonsai plant. Different plants require different mediums, so it is crucial to determine the needs of your plant. Improved cacti mix is an ideal bonsai soil.

The 4 Qualities of Cacti Soil Ideal For Bonsai

Cacti soil is suitable for bonsai trees because of its: 1) drainage, 2) absorption, 2) aeration, and 3) nutrient content.

The substrate demands various qualities to be considered an excellent potting medium for bonsai plants. Here are the four properties of cacti soil that makes it an excellent alternative for bonsai.

1- Excellent Drainage

The ultra porous feature of the cacti mix provides top-notch drainage that favors the roots of bonsai trees. It allows the medium to drain water quickly, keeping the root system moist but not wet.

Cacti mix containing porous aggregates such as pumice and lava rocks drains excess water quickly. Because of their superior drainage quality, your trees will not have the danger of sitting on waterlogged soil and suffer root rot. The porous texture provides permeability to water and allows the medium to retain nutrients by absorption.

2 – Good Absorption

Cacti soil has exceptional water and nutrient retention ability that provides moisture and nutrition to bonsai roots without causing overwatering. The porous substrate absorbs water and minerals, then supplies them to the roots as the water dries up without excessive retention as compost or peat moss would do.

The porous nature of the cacti mix retains a sufficient amount of moisture that lasts in between watering. The few parts of organic matter in the substrate hold minimal water and nutrients without drowning the roots. Cacti mix contains inorganic compounds that do not deteriorate and compress over a particular time.

With cacti potting medium comes a balanced water retention capacity at all times, so you don’t have to worry about your bonsai plant getting too much or too little water. Of course, you need to rehydrate your trees according to their water needs.

And suppose your tree variety prefers a bit more moisture. In that case, you can add a considerable amount of composted bark for added moisture retention or the akadama aggregate, just like the one below from Amazon.

3 – Adequate Aeration

Excellent drainage goes hand in hand with aeration. In general, the bonsai roots can grow freely and easily access oxygen underneath and exchange gases. Cacti mix can provide good air circulation for bonsai roots eliminating the chance of compacting.

The cacti substrate has enough air space, providing room for bonsai roots to breathe. Aeration is crucial in achieving healthy root development to grow a vigorous bonsai tree. Cacti mix encourages robust and lush root build-up.

Its ability to remain loose and not dense is beneficial to the roots. Loosely packed medium with proper aeration inhibits fungi and bacteria underground, keeping the bonsai roots disease-free.

4 – Nutrient Content

Cacti mix not only allows drainage, aeration, and water retention. It also supplies good food suitable for bonsai plants to flourish.

The inorganic constituents of the cacti substrate are equipped with trace amounts of vital minerals such as phosphorus and nitrogen. The appropriate cacti mix has a small portion of organic matter, which is rich in nutrients favorable for the growth of bonsai trees.

Drawback Of Using Cacti Soil For Bonsai Trees

Cacti soil is lightweight due to its porous components. This makes such a growing medium alone not suitable for large bonsai trees as it will not firmly hold the weight of the tree.

Bonsai trees have shallow roots, usually potted on shallow containers. Cacti potting mix being lightweight, cannot support bonsai trees on the pot, especially if the plant is quite large. Suppose you opt to use cacti mix for your heavy bonsai trees. In that case, I recommend adding a bit more lava rock or calcined clay like the ones below available at Amazon for the extra weight of the substrate and to provide more stability for the tree.

Takeaways

  • Cacti mix is the best when it comes to growing bonsai. The mixtures work as good as the bonsai mix because it has almost the same components that provide the same benefits.
  • To make a mixture suitable for bonsai plants, you need to consider the impressive growth of the plant. Bonsai prefers a medium that does not hold too much water and provides adequate aeration.
  • One problem with using cacti mix for bonsai is its lightweight property which poorly provides stability for bonsai trees, especially the larger ones. To solve this problem, incorporate additional aggregate to provide added weight to the medium.

Sources

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Esther

Esther is the self-proclaimed cactusholic :D of the team. She owns a cacti shop with hundreds of plants that she takes care of. Esther has many years of experience in growing and caring for drought-resistant plants like cacti and succulents.

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