Ready-to-use bonsai soil for acid-loving plants - 5 lt pack

What it is and where it comes from

This is a ready-to-use mix, prepared for bonsai grown from plants that need an acid soil. It contains two Japanese components, akadama and kanuma in 2/5 mm grain, combined with an organic part made of universal compost and specific ericaceous compost. It comes in a 5 litre pack, ready to pour into the pot.

How it behaves in the pot

The mineral part governs drainage. The akadama and kanuma granules keep the mass open, water runs through without stagnating and air remains between one granule and the next: that is where the bonsai builds its fine feeder roots, the ones that later withstand root pruning and support a tidy nebari.

The compost fraction works the other way round, holding moisture when the days grow longer and the pot dries out in a few hours. The result is a substrate that does not demand constant watering in summer yet stays well aerated. The kanuma, together with the ericaceous compost, lowers the soil reaction and keeps it within values that acid-loving plants tolerate.

Features

• Ready-to-use soil for bonsai of acid-loving plants
• Composition: 25% universal compost, 25% akadama 2/5 mm, 25% ericaceous compost, 25% kanuma 2/5 mm
• Grain size of the mineral part: 2/5 mm
• 5 litre pack

Which grain and for which plants

The 2/5 mm grain is a fine grade. It is at home in shallow pots, on shohin and on small to medium sized plants, where a coarser granule would leave gaps that are too wide between the roots. On large specimens it works better as filling for the central area, with a coarser material kept at the bottom.

Its natural use is on acid-loving plants: satsuki azaleas and others, rhododendron, gardenia, camellia, and in general anything that turns yellow in calcareous soil. It is used just as it comes out of the pack, or lightened with pumice or lapillus if the climate is damp and the pot dries slowly.

How to use it when repotting

Before filling, a quick sieving removes the fine dust formed during transport: it takes a few seconds, but it stops the bottom of the pot from clogging. A mesh goes over the drainage hole and, if the pot is deep, a layer of coarse granules.

Once the plant is in place, work the substrate down between the roots with a chopstick, moving from the bottom upwards until no air pockets remain. Do not press it down with your thumb. After repotting, water generously until the water running from the hole is clear.

Frequently asked questions

Can I use it on its own, without adding anything else?

Yes, that is what it was made for: the mineral and organic parts are already balanced in the pack. Growers in very rainy areas or those who keep their plants in deep pots can lighten it with pumice or lapillus, to speed up drainage after summer storms.

Is it suitable for satsuki azaleas?

That is one of its main uses. The 2/5 mm kanuma and the ericaceous compost keep the soil reaction on the acid side, which is what satsuki requires. Many azalea growers prefer pure kanuma: this mix is an easier option to manage when watering.

How many pots will 5 litres fill?

It depends on the shape of the pot more than on its diameter. Five litres is enough for a few repottings of shohin and small plants, or for one medium sized pot. It is the right quantity for anyone with just a few acid-loving plants who does not want leftovers sitting around.

What is included

• 5 litre pack of ready-to-use soil for acid-loving bonsai
• Mix of universal compost, akadama 2/5 mm, ericaceous compost and kanuma 2/5 mm

Those who prefer to measure out the components themselves can put together their own mix on the made-to-measure soil page.