AusBonsai

Trawled through these posts, couldn't, find any posts on sterilizing mix. Would this be OK. Thought of placing a small plastic bag in microwave with some in it. Any thoughts.

hey mate i sometimes reuse my mix after sieving out all the broken down organic matter. But only from pots that have healthy trees because i think it contains good bacteria in it. i normally dont use it from a tree that was sick and died. idk bout others but works for me hope this helps

With inorganics in my mix like pumice / scoria I try and reuse, if trees in training or recently collected I use this mix. Same comment as above, would only use if previous plant was healthy. More advanced trees in proper containers I use new mix.

You can sanitise potting mix if you think it is worth it. Sterilisation requires high temps and is not really required. All you need to do is kill off the nasties that affect your plants hence sanitisation or pasteurisation rather than sterilise.
Commercial nurseries used to steam potting mix and containers to get rid of problems.
I believe that 72degrees C is enough to kill most problems. I know some who boil/steam mix and equipment but microwave is cleaner and quicker. You will need to work out how long it needs to bring the quantity of mix up above 72 C for a short while. I put 4 litres in an icecream container on for 10 min (cutting mix).
Keep an eye on your first try. Last time I tried microwaving potting mix it melted through the bottom of the container and caught fire Not sure whether that was the stone or some charcoal that was in the mix but you should be careful until you see how your mix reacts to microwave. Make sure it is damp so there's some water for the microwaves to work with.
Also consider any fertiliser left in the mix. I assume that controlled release prills would burst at high temps and release all the fert in one hit so the mix may be toxic after microwaving if there's much osmocote or similar left in it.

Microwaving potting mix is a bit hit and miss. sometimes you can and some times you blow up the micro wave
I re-use a lot of my mixes because I'm tight and the way I do it is to allow the old mix to dry out some what and sieve it out to get rid of all the fine useless stuff. I then damp it down a little and place it into black plastic bags, until the bags are around 100 mill thick when laid down. The bags are then left out in the sun for as long as possible, usually around a week, turning them after a couple of days. After they have been turned I make sure I flatten them out to a uniform thickness again as well. After a week, or sometimes longer I simply put them away in the shed, ready to be used for the next potting. When that time comes around I simply adjust the amount of organics in the mix by adding a bit of potting mix to replace that lost by all the earlier processes.

You can solarize old mix. Lay down just moist mix about 50mm thick and cover it with clear plastic and leave it in full sun for about 2 weeks in mid summer when the day temp is hot. It's important there is a good seal all around the edges.
Personally I would use fresh mix for important trees.

This season I have reused mix, but only to use in the repotting of the same tree. I figure this is the same as just not repotting it for another season?

I used the old mix for the first ½ to ⅔ of the pot, then used the fresh stuff to top it up. I wonder if this would also help to try lean it toward a stronger lateral root spread having the fresh stuff up high?

Next season I will give it a completely fresh mix and continue to repeat every second year (testing my memory in the process haha).

I don't believe there would be any cons with this as I liquid feed fortnight in the growing season and as stated, it's the same mix from the same tree so there couldn't be any cross contamination?

Cheers,
Pearcy.

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Pearcy, I do likewise. Most of my trees are in big pots for growing on and all new mix every time would be expen$ive.

After cutting back the roots, I use the old stuff in a mound as the base to get the pot prepped, place the tree on that and then pour in fresh stuff. I reuse the same tree's mix, but sometimes use mix from another healthy tree for 'impervious' species, like figs.


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I re-read Bonsai Today #17 again. I usually read the whole thing every spring although I almost have it memorised now
It's worth going over this time of year. I wish they would stop calling it ''transplanting '' though...

treeman wrote:I re-read Bonsai Today #17 again. I usually read the whole thing every spring although I almost have it memorised now
It's worth going over this time of year. I wish they would stop calling it ''transplanting '' though...

Unfortunately I don't have it Mike, are you able to elaborate on what it said at all? Or was it in relation to your earlier post in this thread?

Thanks!

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Pearcy001 wrote:

treeman wrote:I re-read Bonsai Today #17 again. I usually read the whole thing every spring although I almost have it memorised now
It's worth going over this time of year. I wish they would stop calling it ''transplanting '' though...

Unfortunately I don't have it Mike, are you able to elaborate on what it said at all? Or was it in relation to your earlier post in this thread?

Thanks!

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The whole issue is devoted to ''transplanting''

You can quite regularly pick up Issue 17 on eBay. Sometimes at a crazy price, sometimes at a reasonable price.

I know this is an older thread, but I thought I'd ask the question here to keep the ideas together.

I have some high strength hydrogen peroxide left over from another application, and I have heard elsewhere that it is good for killing fungus etc in soil.
If diluted down to an appropriate strength, would it be suitable for sanitizing soil components/mixes for re-use?
As it breaks down to oxygen and water, there's nothing nasty left behind.

Brekel wrote: ↑May 22nd, 2020, 1:19 pm I know this is an older thread, but I thought I'd ask the question here to keep the ideas together.

I have some high strength hydrogen peroxide left over from another application, and I have heard elsewhere that it is good for killing fungus etc in soil.
If diluted down to an appropriate strength, would it be suitable for sanitizing soil components/mixes for re-use?
As it breaks down to oxygen and water, there's nothing nasty left behind.

Not a good idea. Please my above comment of solarization. Other than aerated steam, it's the best way.

Thanks Mike.
I'll have to hope for some sunny Tassie days