Potting mix for Scot's Pine?

I recently acquired a Scot's Pine that needs to go into a new pot. It's collected material, established but not styled. I do not have much experience with pines yet so I'd welcome any input on potting this tree up.

I have at my disposal Sophisticat "Kittydama" (used to good effect for the last 18 months in many other pots), alpine grit, fine chipped bark and John Innes No. 3 compost. I am well aware that I need a free draining mix but would welcome any input into whether I could put together a suitable mix from these ingredients and what sort of ratios I should be looking at? I can also retain and use some of the existing soil that is still of good integrity in order to transfer any beneficial fungi.

Thanks in advance for any input


Matt

I'd use equal proportions of those but leave out the John Innes completely. I prefer coarse chipped bark with the largest chunks passed through a chipper and then graded to remove all fines. You can incorporate any old needles and or some well rotted pine needles from under a scots pine to encourage myc. If you are sure the old soil is healthy and the myc is indeed myc, not wooly root aphid, a pinch of that is all that is necessary to start things off. This keeps all my Scots nice and healthy.

Brilliant, thanks Kev, I'll do that. Don't know why, but having not had a pine before I found myself being very unsure of what to do for the best and I wanted to get it as right as possible first time. As always, it's best to ask and seek the advice of those with the right experience!

Many thanks

Matt

Hello Matt. Is it your intention to remove all the old soil and where was it collected?

Hi Will,

I actually did the repot last night before seeing your reply. I believe the tree came from the New Forest area. I came to "own" this tree via a rather convoluted and complicated way so I'm not entirely sure of it's whole history. Suffice to say, when the tree came into my possession, it was already out of it's old pot and hadn't quite made it into a new one. At the time it was planted in what looked like an Akadama based soil with a yellowish colour and this made up virtually all of the soil in the old pot. Most of this just fell away when I started to clear it. Underneath the base of the tree was a small amount of a grey clay-like (but dry) soil which looked very much like it might have been the original soil from collection. I removed most of this but not all. There was absolutely loads of fine root, of which I kept 90% (just tidied up the ends of the really long ones) as they fitted into the new pot with plenty of room for growth. I put a few handfuls of the old soil (the Akadama type) in the new mix as Kev suggested.

I hope I've done the right thing!