The most common mistake......

Share your ideas on re-potting, potting mediums and fertilisers.
User avatar
treeman
Aussie Bonsai Fan
Aussie Bonsai Fan
Posts: 2836
Joined: August 15th, 2011, 4:47 pm
Favorite Species: any
Bonsai Age: 25
Location: melbourne
Has thanked: 28 times
Been thanked: 571 times

The most common mistake......

Post by treeman »

...new bonsai enthusiasts make - from my observations, seems to be planting trees into too large a pot. The hope seems to be that the tree will grow faster, stronger etc. Very frequently the opposite happens. The tree becomes progressively weaker, the roots stop growing, the leaves lose their luster and cannot photosynthesize properly and cannot form the hormones necessary for root growth. The roots become weaker still. The plant looks wilted. Water is given. Fertilizer is applied. Dying roots begin to rot. The leaves are now hanging on for dear life. They (the roots) have hardly entered the new mix. The tree then either dies outright as soon as hot weather returns or languishes for months doing not much at all. How many times I've seen it I can't imagine.

Why does this happen? One reason is that we tend to apply fertilizer to match the pot size and not the tree size so there is a tendency to over-fertilize. The higher electrical conductivity (concentration of soluble salts) in the mix will inhibit root growth leading to root rot and the death spiral above. The other reason is that bonsai material is regularly top pruned. When we prune the tops we put a stop (or slow down) root growth because we remove auxins which are hormones to stimulate root extension. Auxins are produced by leaves and green stems. Particularly new ones. This does not happen with regular nursery stock which is encouraged to grow full speed without restrictions. The pot soon fills with roots and the tree remains healthy. So, we should be aware that when we prune the top, the tree will need a corresponding reduction in water and fertilizer until it builds branches and new leaves again.

Of course this is just general information and there are exceptions eg; extremely vigorous species which seem to just want to grow regardless of what we do, but even these have their limits. With slower growing plants like pines, it becomes much more important to understand the perils of large pots. The problem is made worse during winter when there is too much water entering the pots and the plant activity is slowed down and we think that just one more branch can be cut off. This is often the proverbial last straw.
All said, it is much safer to always match the pot size with the root size and give more water rather than having a large pot and hoping for the best. It often happens that a tree in a smaller pot will outgrow the same tree in a larger pot due to the above factors. You can assume to be pretty safe if you allow no more than about 50mm of room between the ends of the roots and the inside of the container for conifers and maybe twice that for deciduous trees. You will need to repot more often this way, but there is every chance your material will develop faster than you expected!

I hope that folk new to bonsai find some useful information here and avoid the most common of mistakes........
Last edited by treeman on May 29th, 2018, 4:36 pm, edited 1 time in total.
Mike
Mbunro
Aussie Bonsai Fan
Aussie Bonsai Fan
Posts: 298
Joined: February 14th, 2016, 5:19 pm
Bonsai Age: 1
Location: Perth
Been thanked: 11 times

Re: The most common mistake......

Post by Mbunro »

im assuming all this relates to finished/semi finished trees? and not so much for trees in the grow-on phase.
if im right it mite be worth adding a little disclaimer but if im wrong you have just turned my world upside down ha. :lost:
User avatar
treeman
Aussie Bonsai Fan
Aussie Bonsai Fan
Posts: 2836
Joined: August 15th, 2011, 4:47 pm
Favorite Species: any
Bonsai Age: 25
Location: melbourne
Has thanked: 28 times
Been thanked: 571 times

Re: The most common mistake......

Post by treeman »

Mbunro wrote:im assuming all this relates to finished/semi finished trees? and not so much for trees in the grow-on phase.
if im right it mite be worth adding a little disclaimer but if im wrong you have just turned my world upside down ha. :lost:
All trees. Notwithstanding the ''vigorous exceptions''.
I meant this to be a general thing to keep in mind rather than an unbreakable rule. Circumstances will change if there is little or no organic material, the coarseness of the mix, the control of water and fertilizer etc. With experience you can bend the rules a bit but only if you understand them first.
Last edited by treeman on May 29th, 2018, 5:22 pm, edited 1 time in total.
Mike
User avatar
melbrackstone
Aussie Bonsai Fan
Aussie Bonsai Fan
Posts: 3442
Joined: December 15th, 2015, 8:05 pm
Favorite Species: the ones that live
Bonsai Age: 28
Bonsai Club: Redlands, BIMER, VNBC
Location: Brisbane
Has thanked: 1191 times
Been thanked: 707 times
Contact:

Re: The most common mistake......

Post by melbrackstone »

I've seen this mentioned before, but how does it compare to planting a small tree into the ground?
User avatar
treeman
Aussie Bonsai Fan
Aussie Bonsai Fan
Posts: 2836
Joined: August 15th, 2011, 4:47 pm
Favorite Species: any
Bonsai Age: 25
Location: melbourne
Has thanked: 28 times
Been thanked: 571 times

Re: The most common mistake......

Post by treeman »

melbrackstone wrote:I've seen this mentioned before, but how does it compare to planting a small tree into the ground?
The ground is not a container. Water behaves differently because there is no break in the capillary action so there is no sitting saturation as there can be in a pot. The water keeps moving.
Another way of looking at it is that field capacity (the most amount of water the ground can hold) does not last long. In contrast, container capacity can last a long time if it (the container) is large compared to the volume of roots removing water from it. It then takes a longer time for the roots to get the required amount of oxygen.
Last edited by treeman on May 29th, 2018, 5:34 pm, edited 3 times in total.
Mike
User avatar
treeman
Aussie Bonsai Fan
Aussie Bonsai Fan
Posts: 2836
Joined: August 15th, 2011, 4:47 pm
Favorite Species: any
Bonsai Age: 25
Location: melbourne
Has thanked: 28 times
Been thanked: 571 times

Re: The most common mistake......

Post by treeman »

You will notice that a tree which regularly dries out is always healthier than one that doesn't.
Mike
User avatar
Keep Calm and Ramify
Aussie Bonsai Fan
Aussie Bonsai Fan
Posts: 944
Joined: April 1st, 2017, 11:50 am
Bonsai Age: 0
Location: Newcastle NSW
Has thanked: 397 times
Been thanked: 445 times

Re: The most common mistake......

Post by Keep Calm and Ramify »

:lost: Was I supposed to sign up for Tier 3 membership to receive this valuable information? Shut up & take my money!! ;)
User avatar
melbrackstone
Aussie Bonsai Fan
Aussie Bonsai Fan
Posts: 3442
Joined: December 15th, 2015, 8:05 pm
Favorite Species: the ones that live
Bonsai Age: 28
Bonsai Club: Redlands, BIMER, VNBC
Location: Brisbane
Has thanked: 1191 times
Been thanked: 707 times
Contact:

Re: The most common mistake......

Post by melbrackstone »

Now that makes perfect sense, thanks Mike!

I'll have to repot a few of my plants.... :lol: :lol:
shibui
Aussie Bonsai Fan
Aussie Bonsai Fan
Posts: 7653
Joined: August 22nd, 2009, 8:41 pm
Favorite Species: trident maple
Bonsai Age: 41
Bonsai Club: Albury/Wodonga; BSV; Canberra; VNBC
Location: Yackandandah
Has thanked: 65 times
Been thanked: 1399 times
Contact:

Re: The most common mistake......

Post by shibui »

It is good to see that Mike has added the rider excepting vigorous species. There are also some differences in potting mixes that will probably influence which species will flourish and how much bigger is too big a container for a given tree. I know that I've put smaller plants (vigorous species?) into quite large containers at times and had very good growth but I also accept that some just don't seem to manage with the extra space.

Well explained Treeman.
http://shibuibonsai.com.au/" onclick="window.open(this.href);return false;
Akhi
Aussie Bonsai Fan
Aussie Bonsai Fan
Posts: 416
Joined: March 17th, 2016, 6:10 am
Favorite Species: Maple
Bonsai Age: 15
Location: Melbourne
Has thanked: 27 times
Been thanked: 40 times

Re: The most common mistake......

Post by Akhi »

treeman wrote:You will notice that a tree which regularly dries out is always healthier than one that doesn't.
I can definitely relate to this with my trees


Sent from my iPhone using Tapatalk
Newbie
robb63
Aussie Bonsai Fan
Aussie Bonsai Fan
Posts: 295
Joined: May 19th, 2016, 12:11 am
Favorite Species: figs & junipers
Bonsai Age: 4
Location: sydney
Been thanked: 11 times

Re: The most common mistake......

Post by robb63 »

Thanks T-man
This explanation sheds light on a couple of my trees I put into larger container.
One thing I find difficult as a newbie is leaving stock alone, scissor finger you could call it. :palm:
Anyhow I'm overcoming that problem with more and more trees. That way lots of stock avoids
my over zealous attention and actually gets to grow well.
User avatar
Rory
Aussie Bonsai Fan
Aussie Bonsai Fan
Posts: 2807
Joined: January 23rd, 2013, 11:19 pm
Favorite Species: Baeckea Phebalium Casuarina & Banksia
Bonsai Age: 24
Location: Central Coast, NSW
Has thanked: 22 times
Been thanked: 456 times

Re: The most common mistake......

Post by Rory »

That amount of times I’ve seen this....
You’ve been delving in my brain again Mike. :beer:
Though, you’re probably a lot older than me you fossil. So perhaps it is I who has been dealing in your brain.

viewtopic.php?f=7&t=19878&hilit=+Winter

As mentioned above, I often reiterate that thread above.
Last edited by Rory on May 29th, 2018, 9:06 pm, edited 1 time in total.
Rory
I style Bonsai naturally, just as they would appear in the wild.
Central Coast, NSW
Bonsai: Casuarina Leptospermum Banksia Phebalium Baeckea Melalueca Ficus

Growing Australian natives as Bonsai: viewtopic.php?p=289480#p289480

Buying and repotting Native nursery material: viewtopic.php?f=78&t=30724

Growing tips for Casuarina as Bonsai: viewtopic.php?p=244995#p244995

How to reduce moss from the trunk without damaging the bark: viewtopic.php?p=295227#p295227
User avatar
MJL
Aussie Bonsai Fan
Aussie Bonsai Fan
Posts: 2840
Joined: October 26th, 2014, 8:47 pm
Favorite Species: Maples, Elms, Cedars and Pines
Bonsai Age: 7
Bonsai Club: Waverley Bonsai Group & Yarra Valley Bonsai Society
Location: Melbourne
Has thanked: 424 times
Been thanked: 643 times

Re: The most common mistake......

Post by MJL »

treeman wrote:...new bonsai enthusiasts make - from my observations, seems to be planting trees into too large a pot. ....the tree becomes progressively weaker, the roots stop growing, the leaves lose their luster ...the roots become weaker still. The plant looks wilted. Water is given. Fertilizer is applied. Dying roots begin to rot.

Why does this happen? One reason is that we tend to apply fertilizer to match the pot size and not the tree size so there is a tendency to over-fertilize. The other reason is that bonsai material is regularly top pruned. When we prune the tops we put a stop (or slow down) root growth because we remove auxins which are hormones to stimulate root extension. So, we should be aware that when we prune the top, the tree will need a corresponding reduction in water and fertilizer until it builds branches and new leaves again.

I hope that folk new to bonsai find some useful information here and avoid the most common of mistakes........
Thank you Mike - that paragraph around the two reasons is brilliant. Simple, understandable plain English advice that a novice like me appreciates.

Your observations align to my mistakes ...in the past, I have absolutely applied fertiliser to the pot size not the tree size.... :whistle: and error which I will now avoid!

Cheers

Mark
Tending bonsai teaches me patience.
User avatar
Ryceman3
Aussie Bonsai Fan
Aussie Bonsai Fan
Posts: 2596
Joined: October 19th, 2014, 10:39 am
Favorite Species: Pines & Mels
Bonsai Age: 7
Location: Melbourne
Has thanked: 1042 times
Been thanked: 1535 times

Re: The most common mistake......

Post by Ryceman3 »

It took me 2 years to figure out this exact thing with Mel Lanceolata I had grown from tube stock. They were going great guns... plenty of healthy growth - lots of promise so I chucked them all in oversized pots and was ready to reap the rewards. This bonsai gig was easy!!!
I threw the last one out 2 weeks ago. It had barely grown at all in the 18 months since “over upsizing” ... I couldn’t figure out where I went wrong?? I’m pretty sure what Treeman is talking about is the primary reason for their demise, and I’m pretty sure I have a Coastal Beard Heath trying to tell me the same thing.
Lesson learned (I hope anyway).
It’s good advice Treeman and not often brought up.
:beer:
User avatar
peterb
Aussie Bonsai Fan
Aussie Bonsai Fan
Posts: 731
Joined: October 4th, 2011, 5:09 pm
Favorite Species: olive
Bonsai Age: 5
Location: adelaide
Been thanked: 1 time

Re: The most common mistake......

Post by peterb »

Hi Treeman, that would also explain the demise of my cottoneaster. I was growing it on to thicken, after 3 years I was happy with it and trunk chopped but carried on watering as much as before and 2 months later I threw it out. Seems it couldn't cope with all the water because when I pulled it out the pot all the roots were a soggy rotten mess
Cheers
Peterb
Post Reply

Return to “Repotting, Soil and Fertilisers”