Bonsai Tree Soil Basics

Posted by Nursery Tree Wholesalers on

What makes the perfect bonsai soil? This is one of the most extensively debated topics in the bonsai world. All of the bonsai trees for sale on our online, wholesale nursery come in very suitable, nutrient rich soil that will keep your tree healthy and vigorous for a good amount of time - but if you want to learn more about proper soil composition for a bonsai soil, then this is the article for you. This article is just an introduction to bonsai soils and does not discuss every single ingredient or mix possible (that list is endless!) nor will we recommend with soil is best for you. That is an solution that only you can answer after experimenting with your own bonsai trees over time, following your specific care routines in your specific climate.

What Makes A Good Bonsai Soil?

Bonsai trees are restricted to a very small amount of soil on which they depend on everything for - nutrients, water, and gases. So, it is best to plant a bonsai tree in good, quality soil that will ensure its basic needs are met.

Here are some basic qualities that the soil should have:

  • Water retention - the soil must be able to retain proper amounts of water which supply moisture to the root system in between waterings.
  • Drainage - any excess water needs to be able to drain out promptly from the pot. Many problems can arise from not having proper drainage.
  • Aeration - the roots need oxygen. The particles of the bonsai soil need to be large enough to allow small gaps of air pockets to get to the roots.

With good water retention, fast drainage, and proper aeration, your bonsai tree is bound to stay healthy. Typically, a well structured and particle based inorganic soil will allow for those things. If you have a compacted organic soil, it will certainly lack drainage and aeration which can cause many problems down the road.

Inorganic vs. Organic Soil 

Most bonsai soil mixes will be described as either inorganic or organic. 

  • Organic soil is made up from dead plant material such as bark, leaf-litter, or peat. 
  • Inorganic soil will contain little or no organic matter, but is rather made of up baked or fired clays and volcanic lava.

Organic Soil

In the past, organic soil mixes tended to be used by most Western bonsai lovers and have been used by many bonsai wholesale nurseries. However, when knowledge about bonsai trees began to grow, we realized that most of the components in organic soil are actually not conducive to maintaining a healthy bonsai tree and we no longer use it with the bonsai trees for sale we have in our online nursery. Components such as peat, which can often be too water retentive which will cause the soil to be sodden and possibly root rot during the rainy season. Also, during period of very high temperatures peat can be relatively finicky when it comes to water by leaving dry spots around the rootball.

Most agree that the biggest problem with organic soils is that the particles break down over time. So even if the soil has nicely sized particles to allow for proper drainage in the beginning, the particles will continue to break down as time goes on, causing the soil to become compact. Compact soil drains very poorly and is often airless, which can suffocate the root system.

Overall, organic soil mixes are not the way to go with bonsai trees.

Inorganic Soil Mixes

Inorganic soils takes a very long time to break down, meaning that the particles hold their structure allowing for proper drainage. Most inorganic soil is made up of fired clay or volcanic lava. The particles retain water, but any excess water will quickly flow out of the bottom of the pot. Because of this, it is very difficult to overwater a bonsai tree in good inorganic soil - that is a huge plus. We recommend going through a local nursery or hardware store or even contacting other bonsai enthusiasts around you to see what is available for purchase in your area.

Can You Switch From Organic to Inorganic Soil?

Yes. If you happened to buy a bonsai tree from elsewhere and want to switch your soil from organic to inorganic, you certainly can. Deciduous and coniferous trees will actually benefit from the switch immediately.

So What Is The Best Soil?

There is not a single “best” soil mixture for bonsai trees. There are many variables that come into play. Some species of trees need less water so water retention is not as important, while other trees require large amount of water and need a soil with excellent water retention. It can also be different depending on the climate and rainfall of the area you live in. Because of all these differing factors, it is literally impossible for us to say what specific mixture is the best for you. We recommend that you to contact local enthusiasts to find out what is working for them and where to buy it.

*Whatever soil that you decide to use, we highly recommend that it is inorganic due to the superior drainage qualities and the length in which it takes the particles to break down.

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