Bonsai trees

Replanting and cutting the roots

Just like all plants, bonsai trees grow too - even though remaining little. Their growth is accompanied with the growth of the roots. When the roots fill out the pot completly, it is the right time to replant it into a bigger pot, which allows the tree to have more free space for growing.


No matter if you're experienced a bit or if you're a newbie, youl'll have to replant your tree once for the first time. So the basic questions stands as "When should I replant my bonsai?" The answer is very simple, it's best to replant a tree in the beginning of growing season. Besides the right moment, it's necessary to use the soil very wisely, since it must be of good quality which includes attributes like porosity, etc. The soild must contain enough air when it comes to watering, it should offer good pH values which are required by each bonsai differently. Moreover, the substrate must be able to bind nutriment in the state which allows trees to take and use them easily. Basically, the best soil for bonsai is a mix of ordinary soil, peat and sand. Bear in mind that those elements must be mixed in a pre-defined ration in order to satisfy the bonsai's requirements and to make it live happily. Like humans, every miniaturized tree has different requirements; This difference is the ratio. Sometimes it's possible to replace the sand with another mixture which will allow the soil to be more aerated. We can use pearlite, granulated clay (akadama) or ceramsite. for this purpose. Let's go through the most common types of bonsai soil.

Indoor trees usually demand this ratio:

(Soil 1): 4 parts of argillaceous rock, 4 parts of peat, 2 parts of sand or akadama with granularity 2-4 mm;

(Soil 2): 3 parts of argillaceous rock, 5 parts of peat, 2 parts of sand or akadama with granularity 2-4 mm;

Use following ratio for outdoor bonsais:

(Soil 3; basic): 1 part of argillaceous rock, 2 parts of peat, 2 parts of sand or akadama with granularity 2-4 mm;

(Soil 4; pervious): 1 part of argillaceous rock, 1 parts of peat, 3 parts of sand or akadama with granularity 2-4 mm;

(Soil 5, lime-free): 1 part of argillaceous rock, 3 parts of peat, 3 parts of sand or akadama with granularity 2-4 mm;

It's recommended to disinfect the soil before it's being used. Use two pans; the first will include water and the smaller pan. Then boil the water (100°C) so it will kill all disease-producing elements and pests. When this is done, sift the soil in order to divide small and large elements. After this step, mix it with some organic fertilizer rather than inorganic. Unlike organic fertilizer, the inorganic will be used faster and it's effect will not remain long enough. Mixing 2 or 3 grams of fertilizer with 1 litre of soil substrate is the most recommended ratio. If you're experienced enough, you can try changin the pH values if necessary. Naturally, the first step is to determine the momentary pH level. You can get the pH values easily by mixing some amount of soil with distilled water. Then measure the pH using the litmus-paper which will show you actual pH value. In case the pH level is low, use 1g of CaCO3 per 1 litre of substrate which will increase pH from about 1/2 to 3/4.

Of course, you can buy special bonsai soil in various shops devoted to bonsai trees, or gardening tools shops nowadays. This is the best way for beginners in my opinion. On the other hand, professionals mix their own substrates. The bonsai guide, which is present on this site contains details of which kind of soil each tree demands.

Roots cutting

Many people suppose that roots cutting will result in stopping the growth or even they think the tree will die. I must disagree, since proper maintenance of roots turns to desired design and helps the tree to grow "as we wish". Naturally, cutting roots is very delicate and should be done very wisely. First, remove the bonsai tree from a pot in order to see how it's roots grow. If they muffle around the bottom of pot, it's the time for cutting. Basically, roots cutting isn't as easy as twigs cutting if you do it for the first time. It's because roots are branched less or more. Roots cutting should go hand-in-hand with leafs cutting, because roots deliver water into the entire tree and water evaporates through leafs. Once you disrupt the stability, your tree could come into troubles and could die too. After cutting roots for the first time, the tree will develop new roots and you'll see them next time when you cut them. Further cuttings should be easier than the first one.

Roots cutting should be done after purifying roots from soil. Dead roots should be removed at first by special bonsai scissors. Reduce living roots by about 50%. However, when cutting a tree for the first time, you shouldn't remove more than 20% of roots. Monitor the tree if it recovers. If the tree drops leafs, you've removed more roots than necessary. Immediately remove leafs and move the tree to a dampy place in order to reduce the evaporation process. Once it will develop new leafs you can move it back to it's original place and position.

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