Potting / Akadama Question

I am very much a beginner at bonsai but this coming weekend will be raiding (with permission!) an area of forestry for material to work with. My intention is to pot whatever I can find in akadama.

My question relates to the transition from organic soil/compost to non-organic potting medium. Is it best to remove as much of the soil as possible from the root system before potting in akadama or is it OK to leave a fair amount on there? I'm not sure if a mixture of the two would be likely to cause any issues.

Any help, suggestions etc. much appreciated.

Wow, Akadama? And, you are very much a beginner? Akadama is imported and rather pricey to obtain here in the New World.
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Use of this rare stuff to initially pot up collected material is a bit of a novelty idea for me to consider, at least....
Removing ALL of the ground/field soil from collected material may - or may not be - a good idea. For me, that depends a lot on the species I have collected. For instance, with collected pine trees I always leave in a good bit of the original soil because of the beneficial bacteria called Mycorrhizia that should be living happily down in with the roots of the pine tree. Initially removing all of the field soil after collection can make it pretty hard for a pine tree to get established in a pot. The same also goes for wild collected juniper trees. The rougher and harsher the growing conditions have been for the tree on the collection site, the more field soil (Called 'Duff') you want to initially leave in with a tree like that.
But, those are evergreens. And, wild collected evergreen trees can often be a little more difficult to establish initially in pot culture. For my own local deciduous trees however, such as the Carolina Hornbeam, Carpinus caroliniana or perhaps the Red Maple, Acer rubrum the roots are much less tricky to work with. In clay soils the garden hose is actually employed with a strong jet of water, to blast out that mucky soil from collected material. Bare rooted! But, once again there are differences. Using such drastic measures to clean the roots of wild collected Beech or Live Oak trees in this area, would be an act that was tantamount to a death sentence for these species.

So, bottom line? I would get with your local Bonsai Club first, before collecting any trees, and ask the members of that club to share any information they can on what they know of collecting local tree material for use as Bonsai. This will surely increase your chances of success in properly collecting some nice material and then actually keeping it alive afterwards to grow and develop into Bonsai.

Thanks very much for your advice, Auballagh.

I keep reading about how expensive akadama is! I bought 14 litres for £14 (around $20) which to me doesn't seem all that much. Unless my calculations are way off I think I should be able to pot between 4 and 5 small trees in pots measuring 250x175x70mm with that amount of akadama. Obviously relative to other potting mediums it may be expensive and I can imagine for those with larger collections the cost may outweigh its benefits.

The trees I will collect will most likely be deciduous species which I think will react fairly well to being bare-rooted, or at least having the majority of the soil around the roots removed, before potting.

I definitely intend to join a local club. Unfortunately it seems I've chosen the wrong time to develop an interest in bonsai as here in England we are very much on the verge of entering spring, so time for collecting and potting new material is fast running out. In fact I fear I may even be at least a week or so too late however will collect what I can and see how it gets on.

Thanks again for the reply.

No worries, glad to help!
I can offer you a couple more to consider if you like.
1) You may not be running that late for this collecting season. For example, a nice bonsai species that lives naturally in your neck of the woods is the English Oak, Quercus robur. Fantastic material. But, like all oaks it can be a bit fastidious regarding collecting methods and most especially - the time of year it's pulled out of the ground. I MOST STRONGLY advise you to collect Oak trees only when you see evidence that they are truly emerging from winter dormancy. When you see those leaf buds swelling and getting fuzzy, that is the safest possible time to collect this species. If you go too early and pull oaks out of the ground before the tree is moving energy up the trunk, you will almost certainly be dealing with a lot of bad complications, (including possible death of the tree!).

2) Be picky. I know..... this is probably very early in the game here for you in keeping these cool little trees, and the natural tendency is to Go Big - Early. Unfortunately, a lot of us have regretted doing just that when we started out in this hobby, and we all pretty much wound up with pretty marginal tree material to work with, (myself definitely included). So, do a lot of looking in those woods and really - REALLY - look hard at the base of trees that interest you, where those roots come out. If that trunk base (Nebari) looks weird, messy or just not right in the Ground? Trust me - it may NEVER be fixed and look quite right in a bonsai pot! (At least in the time it takes to successfully accomplish the fix while you are still alive.....).

And most of all - have fun! Happy hunting and Good Luck!