I am looking for a potting soil recipe for shrubs and trees. Does anyone have any suggestions?
Commercial growers rely heavily on bark mixes, for drainage - the most important consideration - and weight.
I shift quite a bit of my nursery stock, and have good results with a 50:50 mix of Promix potting soil and bark.
The commercial products are weed-free, and drainage is assured.
Does the Promix already contain the bark or is this something that you mix yourself? I am looking at making my own. I thought it would be cheaper than purchasing the bags like I have done in the past for perennials.
Promix is just a brand of good quality commercial grade potting mix. I grab bags of pine bark mulch from our bulk goods. No, this is not a cheap solution. But it is consistent, light weight, weed free, and excellent drainage.
here is a simple tree and shrub mix from Dr Bert Swanson, retired professor of horticulture (specialization in nursery management) at the University of Minnesota:
5 parts composted wood chips (wood chips which have been composted for a year with fertilizer, in his case, turkey manure, added to the chips)
2 parts peat moss
that is a very simple mix.
a mix used here at the nursery I work at is
5 parts peat
2 parts sand
2 parts topsoil
2 parts bark chips
a lighter version of the above mix (for plants that need more well drained)
5 parts bark
4 parts peat
1 part sand
I agree with Brian - Promix is expensive, but it is really good. The fact that it is weed seed free is important.
good luck to you.
This gives me something to work from. I know what you mean about the "weed free". I purchase organic potting soil by the truckload for my perennials and it is like black gold, however, the weed seeds love it to.
2/3 coarse fir bark, 1 part peat moss, 1 part coarse perlite, 1 part micro-nutrient...Works for me, and been going strong for 15 years.