Bonsai Pot mix research driving me crazy (Melbourne)
Posted: September 5th, 2021, 1:22 pm
G'day all!
Long time lurker, first time caller (???), all that stuff!
It's coming to that time of year, when I finally have the free time to start training a few random Junipers I bought from "the place with the sausages out the front" a year ago, and some eucalypts, callistemons and hakeas obtained from work in the wholesale nurseries. I started my collection about 10 years ago with a few items from Gardenworld/Collectors Corner, and started working on a couple of junipers I'd grown from cuttings, but never actually properly planted a specimen in to a real "bonsai pot" (as opposed to a typical 200mm black nursery growing pot).
I'd like to start properly potting some specimens this year, so that I can say I actually HAVE "a real bonsai", but I'm hitting a brick wall when it comes to availability of materials for the mix. I understand that it needs to be free-draining to provide aeration, have good water retention, and offer a decent amount of cation exchange capacity. My pre-bonsai growout pots have mostly been a mix of coir peat, builder's sand, composted pine bark, perlite/vermiculite, some 2mm scoria/pea gravel, and a pinch of "water saving crystals" (ie. polyacrylamide), which has served me well in terms of growth and ease of watering.
I've come at a crossroads in that I've been pulling my hair out trying to find suitable media for my actual bonsai pots (not growing pots, I mean the actual Bonsai pots):
- Diatomite (used to exist in 2-4mm granular form, but now I can only find powdered form for livestock mineral supplement)
- Zeolite (exists in the Woolie's cat litter orange bag, and can get from petandgarden.com.au, but it's in NSW. I have a couple of hundred kilos of this stuff, but it's <1mm in size and came from a pool filtration system)
- Akadama (nope, stupidly expensive to import. Is there anything similar that breaks down over a few years to allow root ramification?)
- Debco's Bonsai Mix (the one apparently designed by the Koreshoff's. All the mentions of this on the forums are from 2011 or so. Debco was bought by Scott's, and Scott's only makes the Osmocote branded "Bonsai Mix", which is basically just regular composted pinebark with polyacrylamide, so completely useless)
- Decomposed Granite (this is frustrating, because I live five minutes away from a damned granite quarry in Lysterfield, but I can't find DG in Melbourne! Does it need to be granite, or will any inactive gravels do as ballast?)
- Coir peat (this stuff is awesome, and I'll probably be using it forever as a water retention media)
- Compost (composted pine bark works well, but I don't feel comfortable repotting and trying to get new roots to grow in a media with anything higher than a 10% portion of composted cow manure, so I prefer to just add fertilizer later down the track)
- Sand (Coarse propagation sand seems to work well for providing drainage and ballast, but that's about all it's good for)
The tubestock I've purchased from Yarra Valley Nurseries (ie. the nursery wholesaling to the big shop with the sausages), seems to be pinebark with no grit, with some slow-release fertilizer balls mixed in, so it basically looks like it's the Bio Gro product from AGS (Australian Growing Solutions, who used to be Debco before they split retail from wholesale/commercial). Great for growing out, not great for ramification and eventual development of shin roots in a training pot.
The shohin bonsai you can get from the shop with the sausages, I'm pretty sure they come from Collector's Corner / Paradisia Nurseries, who make great stock, but when I looked at the top layer of soil, it was GLUED. Somebody had put so much glue in to the top layer that I couldn't even pick one of the rocks off with my fingernail. It looked like they'd used 3-5mm shale as a mulch. Since the big shop with sausages is closed to the general public and they're empty, I grabbed the nearest hose and poured a little bit of water from it on to the topsoil: it just ran off the top. It's as though they've been bottom-watering the plants. I don't think I'll be doing that, thanks. I can understand why it'd be easier to mass produce and ship plants where the soil won't fall out, but you've got actual plant-delivering couriers for that, and you don't need to pack them up in cardboard boxes.
Is there anybody out there in Melbourne, possibly a member of Nursery & Garden Industry Victoria (NGIV) who knows of wholesale suppliers that'll sell at least the components I can use to make a decent mix for keeping natives in a bonsai pot? I'm going crazy here. I can buy wholesale from places like Plantmark, Warner's, Southern Advanced Plants, Paradisia, AGS, GCP, etc., as I'm an apprentice horticulturalist for wholesale nurseries, do some maintenance work on the side, and operate a sole trader operation for selling at markets (and yes, I'm branching in to Bonsai, but will mostly only be selling hardy natives and junipers to the general public).
Long time lurker, first time caller (???), all that stuff!
It's coming to that time of year, when I finally have the free time to start training a few random Junipers I bought from "the place with the sausages out the front" a year ago, and some eucalypts, callistemons and hakeas obtained from work in the wholesale nurseries. I started my collection about 10 years ago with a few items from Gardenworld/Collectors Corner, and started working on a couple of junipers I'd grown from cuttings, but never actually properly planted a specimen in to a real "bonsai pot" (as opposed to a typical 200mm black nursery growing pot).
I'd like to start properly potting some specimens this year, so that I can say I actually HAVE "a real bonsai", but I'm hitting a brick wall when it comes to availability of materials for the mix. I understand that it needs to be free-draining to provide aeration, have good water retention, and offer a decent amount of cation exchange capacity. My pre-bonsai growout pots have mostly been a mix of coir peat, builder's sand, composted pine bark, perlite/vermiculite, some 2mm scoria/pea gravel, and a pinch of "water saving crystals" (ie. polyacrylamide), which has served me well in terms of growth and ease of watering.
I've come at a crossroads in that I've been pulling my hair out trying to find suitable media for my actual bonsai pots (not growing pots, I mean the actual Bonsai pots):
- Diatomite (used to exist in 2-4mm granular form, but now I can only find powdered form for livestock mineral supplement)
- Zeolite (exists in the Woolie's cat litter orange bag, and can get from petandgarden.com.au, but it's in NSW. I have a couple of hundred kilos of this stuff, but it's <1mm in size and came from a pool filtration system)
- Akadama (nope, stupidly expensive to import. Is there anything similar that breaks down over a few years to allow root ramification?)
- Debco's Bonsai Mix (the one apparently designed by the Koreshoff's. All the mentions of this on the forums are from 2011 or so. Debco was bought by Scott's, and Scott's only makes the Osmocote branded "Bonsai Mix", which is basically just regular composted pinebark with polyacrylamide, so completely useless)
- Decomposed Granite (this is frustrating, because I live five minutes away from a damned granite quarry in Lysterfield, but I can't find DG in Melbourne! Does it need to be granite, or will any inactive gravels do as ballast?)
- Coir peat (this stuff is awesome, and I'll probably be using it forever as a water retention media)
- Compost (composted pine bark works well, but I don't feel comfortable repotting and trying to get new roots to grow in a media with anything higher than a 10% portion of composted cow manure, so I prefer to just add fertilizer later down the track)
- Sand (Coarse propagation sand seems to work well for providing drainage and ballast, but that's about all it's good for)
The tubestock I've purchased from Yarra Valley Nurseries (ie. the nursery wholesaling to the big shop with the sausages), seems to be pinebark with no grit, with some slow-release fertilizer balls mixed in, so it basically looks like it's the Bio Gro product from AGS (Australian Growing Solutions, who used to be Debco before they split retail from wholesale/commercial). Great for growing out, not great for ramification and eventual development of shin roots in a training pot.
The shohin bonsai you can get from the shop with the sausages, I'm pretty sure they come from Collector's Corner / Paradisia Nurseries, who make great stock, but when I looked at the top layer of soil, it was GLUED. Somebody had put so much glue in to the top layer that I couldn't even pick one of the rocks off with my fingernail. It looked like they'd used 3-5mm shale as a mulch. Since the big shop with sausages is closed to the general public and they're empty, I grabbed the nearest hose and poured a little bit of water from it on to the topsoil: it just ran off the top. It's as though they've been bottom-watering the plants. I don't think I'll be doing that, thanks. I can understand why it'd be easier to mass produce and ship plants where the soil won't fall out, but you've got actual plant-delivering couriers for that, and you don't need to pack them up in cardboard boxes.
Is there anybody out there in Melbourne, possibly a member of Nursery & Garden Industry Victoria (NGIV) who knows of wholesale suppliers that'll sell at least the components I can use to make a decent mix for keeping natives in a bonsai pot? I'm going crazy here. I can buy wholesale from places like Plantmark, Warner's, Southern Advanced Plants, Paradisia, AGS, GCP, etc., as I'm an apprentice horticulturalist for wholesale nurseries, do some maintenance work on the side, and operate a sole trader operation for selling at markets (and yes, I'm branching in to Bonsai, but will mostly only be selling hardy natives and junipers to the general public).