Try the Bonsai forum for good soil recipes for potted conifers. They are the experts...

Pine bark compost.

Good luck with your question Jeff. I asked the same a year or so ago and the best response I got was a professional mix - but no explanation as to what made up that professional mix.

i moved 4 inch pots to one gals ... with 50% soil less peat mixture .... 50% mini bark chunks ... and 50% sand ... lol...

the sands only function was to add weight .... unless you have a couple thousand to hold each other up .... the wind tends to blow them over .... so sand just for weight ...

try 40-40-20 ...

the whole point.. no matter what the mixture... water goes in the top and straight out the bottom .... and the 'watered' pot barely weighs an ounce more than it did dry ...

you do NOT want you medium to 'hold' barely any water ...

and using the peat mix also ads in the perlite and vermiculite ..

good luck

ken

Conifers, and all plants for that matter, need to have better drainage when grown in container culture as opposed to the ground. Better drainage results from having relatively coarse particles in the container mix, not from adding sand and not from having one coarse layer on the bottom of the can.

I think the only characteristic that differentiates conifers from other plant material is that generally conifers are less tolerant of having their roots damaged during re-pots and pot ups than deciduous stuff. So I think the most important factor to consider when thinking of a mix for conifers is something that lasts for 2 or 3 years as opposed to 1 or 2.

Composted pine bark fines are a good component or even as the only component. Peat doesn't last as long and becomes dense over time, but it's fine too as long as you dont use too much. Perlite is good. I like turface, which I learned about in the container forum. I've experimented with different recipes and this is what Im doing now:

2 parts off the shelf peat based potting mix (or just peat)
2 parts composted pine bark
1 part turface