Choosing the right soil is crucial for the success of your bonsai tree because the correct soil provides all the essential minerals your tree needs to grow fast, healthy, and strong. There is no one-size-fits-all solution because the type of soil you need depends on the kind of tree you are growing – which is why we have compiled this list of different types of bonsai soil mix and where to buy it.
Different types of bonsai soil mix
There are specific characteristics you have to look for when choosing your bonsai soil mix. The best soil provides proper aeration and minerals for the roots, and also sufficient water drainage without compromising on water retention. No single type of soil can provide all of these characteristics, which is why it’s best to use bonsai soil mixtures.
Typical components of such mixtures are organic potting compost, diatomaceous earth, akadama, lava rock, fine gravel, and pumice.
Organic potting compost
Quality organic potting soil is rich in nutrients and bonds the other components used in your mixture together.
Diatomaceous earth is a naturally occurring, nutrient-rich, soft rock that crumbles easily. It’s sometimes used as a bonsai soil mixture because it effortlessly absorbs and holds large quantities of water while allowing for sufficient air to travel through.
The Japanese word akadamatsuchi translates to red ball earth and is a red-colored hard-fired clay found naturally in Japan near volcanoes. Although being the most expensive bonsai soil additive, it’s preferred for its ability to absorb and hold water while providing adequate drainage. The only downside to using akadama, apart from its price, is that it breaks down after a couple of years, which means that the bonsai will have to be repotted.
Lava rock, also known as scoria, is a favorite among many bonsai enthusiasts because it adds sufficient spacing while the rock pores absorb moisture and other nutrients. It also adds an element of beauty, which is why you will often see these lava rocks at bonsai exhibitions.
The best fine gravel you can use in your mix is river rock, which can be found just about anywhere. It’s non-absorbent and allows for proper aeration.
Pumice is an air-filled rock that forms during volcanic eruptions. It’s great as a bonsai soil additive, thanks to its ability to absorb water and nutrients while allowing aeration.
Peat moss, a natural dark brown fibrous material, forms when dead plant matter, moss, and other organic matter decomposes. It’s usually used as a seed starter, an ingredient in potting mixes, and even in hydroponics.
Peat moss can hold several times its weight in moisture, and when dry, it becomes extremely hard and compact – which is why it’s always best to mix it with aggregate material for proper drainage and aeration.
The best bonsai soil solutions
Here we have listed some of the best bonsai soil mixes for your tree.
Hoffman Canadian sphagnum peat moss – 18 quart
This bag of premium-grade Canadian sphagnum peat moss is a great additive to your bonsai soil.
It loosens the soil while increasing its capacity to hold water and nutrients – which in turn stimulates root growth.
The product also works great as a soilless potting mix when blended with vermiculite and perlite.
Red Lava Rocks – 2.2lbs
These 100% natural red lava rocks come in a 2.2lbs bag and each rock measures around 3 to 6mm.
They are a great addition to a bonsai soil mix as the rocks excel at absorbing water and re-releasing it to the roots – thus preventing overwatering and root rot.
Apart from being used as a soil additive, it can also be placed on top of the soil as a top dressing to give your bonsai a magnificent look.
The product has dimensions of 9.06 x 6.97 x 2.4 inches and weighs 2.2 pounds.
Bonsai pumice – 12 dry quart
Pumice is a volcanic rock that is a common mixture used in bonsai soil.
The reason for its popularity amongst professional bonsai practitioners is its ability to retain the moisture from watering while allowing sufficient air to the roots.
Another remarkable quality about pumice is that these rocks never break down so they can be continuously reused.
This pre-sieved 12-pound bag of pumice has dimensions of 17 x 4 x 13 inches.