| Transplanting and Repotting |
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| The purpose of repotting your bonsai is not purely to replace some soil, remove a few roots and maybe change its pot. Its the one opportunity that comes around every two or preferably more years that you can correct any faults in the roots, inspect their growth, look at the soil consistency and make changes to the soil etc. Often people repot for the wrong reasons. Usually because they want to “finish” the tree and get it in a better pot. This is not the best reason to repot as you are putting your need to see a finished tree before those of the tree and a tree that is not strong or still recovering from a previous styling operation will suffer further. Worse still is the situation where the tree is repotted several times, each time the owner is not happy with the pot so swaps it. This will result in a dead tree! Because the roots are hidden by soil, poor repotting often goes unnoticed for some time. But the tree will not thrive and maybe never become a good bonsai if not repotted properly. Remember that bonsai take many years to become damaged from infrequent repotting but are damage very easily and can die from being repotted too often. The following is a check list that you should stick too. It isn’t rocket science but people often compromise on these steps through laziness. No excuses! |
| Sift the soil to get rid of the dust. Sift to the correct particle size for the bonsai. Not forgetting drainage layer and top dressing. Use a drainage layer of one particle deep no matter the size or style of the tree. Fasten the drainage mesh flat over the holes in the pot. Think about your anchorage wire. Measure and pre bend it to the size you require so that there is no slack. Make sure that your repotting bench is perfectly horizontal. Do not force, pound or over work the soil into the pot. This will just crush the soil and your tree will have its feet in wet mud. Yeuch! |
| Soil mixes: Everyone has their own mixes and as no-ones watering routine, feeding regime or climate is the same this is how it should be. But consideration has to be given to the soil components in conjunction with the age, vigour, specie, developmental stage of the tree. Remember that once broken down, a soil will fill the gaps between your free draining material, rendering it useless. So adding grit to a mix is pointless if the other components quickly deteriorate. |
| Properties to consider How much water the soil holds? What specie of tree you are planting in it. What level the bonsai is at. Is it still being developed or is it “finished”? How much nutrition is held in the soil? How much air can be held by the soil? How quickly does the soil break down? What is the PH of the soil? Is this suitable for the tree? |
| Japanese Soils Often disregarded by the “old school” in favour of other native mixes but these soils have come down so much in price and because there is so little waste, now prove value for money. They have been tried and tested! Akadama- This is the now widely accepted No1 soil. Buy the double line, hard kind. In Japan I used no less than 60% akadama in any mix. Kiryu- This is a porous sand, Light yellow and orange in colour. Kanuma- This is the soft, yellow soil usually reserved for Azaleas and other ericatious plants. Often used in a 100%mix. Fuji Sand- A black volcanic sand. It holds more moisture than Kiryu but in the UK is more widely used for top dressings. If used in the mix, no more than 10% is used. River Sand- A very rapid draining non porous material. Often used for conifers that prefer dryer conditions. Keto- This is the black “mud” used for rock plantings. Kneaded with 50% akadama it become pliable and ready to use. Hyuga – This is a pumice type soil. It is very light and has good moisture retention. Like Fuji sand, don’t use more than 10% |
| UK Soils I personally would not recommend using peat, topsoils or humus based commercial soils. Once sieved, they leave a great deal of waste material plus they break down quickly. Bark – The fine, hard bark used for orchids is best. This is usually obtained from Pine or fir. Some can contain large chunks and dust so shop around for the best. A product called Cambark has proven to be the best quality. Kyodama – A product marketed by Kyoto Bonsai Company. It is a porous grit, already sifted and can be used instead of Kiryu although. Horticultural grit- Available from garden centres. Do not trust the label that often says “washed and graded” they lie! You will have to wash and grade it yourself. Biosorb (Moler) – Similar again to Kiryu in that it is a hard absorbent grain. There are similar products to this such as Fullers earth and pumice. They can be used in conjunction with other drainage materials but should not replace them. |
| All these ingredients are available from pretty much every bonsai dealer. All soils must be sieved to be an equal size and contain no dust. Sieve it to grade it and sieve it again to remove ALL the dust before it goes in the pot. Soils that have been left to stand for any length of time should be sieved again. They type and consistencies of soils to use come with experience. Start with a basic recipe and adapt it from there. Basic recipe suggestion 3 parts hard Akadama 1 Part Horticultural grit 1 part Kiryu, pumice, kyodama or another absorbent grit. All graded to the same size. Most bonsai sieve sets have just 3 screens. Trees do not come in three sizes so you will have to adapt and make more and also use kitchen sieves. Re-using soil components is ok for potting seedlings up, using for collected material or digging in to the garden but I would not recommend it for your better trees. |