Saturday, 2 March 2013

repotting and bath time ??????

Wednesday was our Cornwall Bonsai Society monthly meeting and Feb is always a bit of an in between month so it was billed as 'potting soils, pots, hints, tips and observations'.

The club is like most county clubs I guess - a few very keen members, a lot who enjoy bonsai as part of their varied horticultural interests, some new members who are eager for knowledge and some who've been doing there thing for a great many years unchanged. In conversation the topic of who uses what soils came up.........and varied from soil dug from the garden, john innes no2 or home made compost mixed with cornish grit (silver / white granite chips), cat litter (just 1 member now) and various blends based on Akadama, Kiryu, Kanuma, Pumice etc.

It is interesting that my personal observation seemed to show the owners of the more show-able trees, and certainly the trees that are improving rapidly rather than just free wheeling  all use the akadama based soil mixes - and this is an observation that extends to the trees in just about every bonsai show I've been to. Funny thing is I find  users of imported soil ingredients always seems to be open minded enough to consider  tweaking their recipes - adding or dropping an ingredient etc to get even better results - I was using fine bark as 10% of my mixes - but later research shows it depleats the nitrogen in the soil as it breaks down - I want my tree to receive the nitrogen content of the fertiliser and not the potting medium so from now on the bark is gone for good.  In complete contrast to this it seems the compost/soil advocates seem to resist change for a long time claiming not needing the change as the trees have always lived ok, or the cost of the soil components are too high. (My feelings on these points are from observation) a tree may be living ok, but if it is not really improving for one or two decades at the rate it should this is not really an resounding bonsai success.

Cost is a factor to soils, but looked at it objectively it is not expensive in the bonsai scheme of things....Last year I had 20 large treees to do. Soil costs were about £135 delivered. simple breakdown is £6.50 per tree and it will last an average of 5 top quality soil for a large tree is under £1.50 per year, proving soil costs are tiny compared to tree or pot values. Trying to make it even easier and help others to improve their trees a bit I opened up sacks of akadama and also fully blended soil mix (of akadama, kiryu and pumice  -no cheap filler ingredients) and offered 1 liter buckets on the night & 5 liter buckets (for £5.00) and single 14l bags for £12.50. Nobody had really can lead a horse to water etc etc - The flip side of this are the keener members who have really dented the soil delivery already this year so it seems to back up further my early observations.
2 line akadama in 2 grades, kiryu, kanuma, ezo and pumice - everything needed for every bonsai

As the chat moved on watering and its relation to soil ingredients came up - it was interesting that some people were potting all their trees in exactly the same mix - compost/grit combo and trying to water differently depending on species. I felt this is going about bonsai growing in Cornwall completely the wrong way - if you decide to control how much and how often you water to keep a tree happy the theory goes out of the window when it rains for a week, or a month! We have a very mild but wet climate so you have very little control over watering unless you build a roof over the trees. I tried very briefly to explain how i mix soils to have more or less water retention depending on species and then watering can be the same - but i dont think i got the point over clearly so it was mis-understood.

Thinking it over it the next day i realised that if someone did  not know about the properties of various soil components my soil mixes would make no sense and this comparison came to me ( i needed a bath !)..

we have a bath sponge, a pumice stone and a rubber duck. if my bath is full of rubber ducks and i pull the plug basically all the water runs out......if i have a bath full of pumice stones most water runs straight out but 20% or so soaked inside the stones so it drips out slowly over the next few hours.............but my final bath is full of sponges so when the plug is pulled half the water runs out quite fast and the other half slowly drains from the sponges, but they stay wet for hours and hours. this is how soil components work - holding some, lots or little water. for me akadama is the sponge, the pumice stones are kanuma, ezo grit or actual pumice and the rubber ducks are kiryu so by varying the levels of each it is easy to control how much water holds in the pot and the rate it is released or held is easily controlled  Making the soil right is another time saver and adds to the 'making bonsai easier' category or one less thing to worry about. This is even more important in the wet conditions down here  as we cant properly control  how much water or how often a tree gets watered  in the periods of prolonged rain. There are bound to be better analagies.....but i needed a bath at the NO i dont have a bath full of rubber ducks! haha

These days i mix the soil up for a specific tree or species just varying the percentage of akadama from 20% to 50% ( lower amounts for 'dryer' trees) and then equal parts kiryu and pumice or ezo. If i had a real water lover i would up the akadama a bit more, and if i have a tree with weak roots for some reason i add chopped sphagnum as it certainly promotes new root growth but does hold a lot of water so care in needed.
My best 'tree rescue' soil mix is one third chopped live sphagnum and two thirds kiryu - the moss gives the air pockets and humidity while the heavy kiryu gives stability to the planting.

The Peter Warren March workshops at No.16 are coming up soon now and everyone is looking forward to a few days increasing their bonsai awareness and skills. This is the second series of workshops we've organised down here and it will be so rewarding to see the improvement  in the standard of local trees over coming seasons. You find there are hot spots across the country where effort is made to want to improve - usually centered around  a good nursery, a very high quality club or a group of like minded individuals. In Cornwall we have a very enviable growing season , great water quality and very mild winters by UK averages so the bonsai.@.16 project is aiming to increase the knowledge and to offer the type of quality material that bonsai enthusiasts really want. Many plans are in the pipeline including a free practical bonsai workshops one saturday a month - most likely the 4th saturday as our club meeting is 4th wednesday. We are right behind Tesco so combine a bit of bonsai therapy with the weekly shop . More updates as they happen.

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