AusBonsai

Mark Rockwell once wrote on a forum that:

"99% of all diseases are caused by over watering"

I've been growing bonsai for over 25years, and have killed lots of trees from poor watering. It took me a long time (many years) to realize that I wasn't watering carefully enough. Since I've changed to course soils and changed watering practices I've seen a dramatic drop in pests and diseases.

Do you instinctively reach for a spray when you have a problem, or do you consider there is something a little bit more subtle going on?

Happy to discuss this,

Paul

http://walter-pall-bonsai.blogspot.com/ ... -myth.html

[/quote]Modern substrates have created a very different situation than what is described in most bonsai books. What is a modern substrate? Well, anything like akadama, pumice, crushed lave, baked loam, turface, Styrofoam flakes, coconut crush, seramins and hundreds of other materials. They all have a couple of properties in common: small particles of even size which don't decompose or decompose slowly; ability to work as water buffer - take on water and and release it alter; due to the coarseness drainage is good and aeration; OXYGEN gets to the roots easily.[quote]

Many in the bonsai world are not using these types of medium. Also pour size reduces as roots fill the voids, increasing water holding capacity, reducing the amount of oxygen available to the roots.

Over Watering once again becomes a problem.

Paul

I didn't get a chance to re-read it and I thought that might be comming
I tend to agree with you to some regard my heavy organic stock mix this year has been an issue that may have contributed to my Trident issues but I don't think that is all it is

With due respect to Mr. Pall and Mr. Rockwell, there opinions have little to do with trees half a world a way. How can anyone but an Aussie know there environment, much less micro-environment but an Aussie. Then with as big and far flung as your continent is you might even question if a Aussie from Sydney knows what is required for a tree in Perth.

You need to figure out what specifically your trees need in your neck of the woods...better yet what it needs on your block. Micro climates have a whole lot to do with trees performance. When I moved a few years ago, just an hour and a half north of where I previously lived, I thought no sweat...everything is basically the same. Same number of rain fall days, temps on average were 2 degrees lower, same average number days of sun. BOY, WAS I WRONG! My new micro-climate was very different wind, humidity, pests among other things gave me a scare an a half.

I had to re-learn what my trees wanted in in this new environment. So besides close observation, I sought out help from anyone who had remotely valid credentials, local farmers, nurseries, the local government agricultural extension, etc. Don't let the debate on water blind you to other possibilities, perhaps possibilities that you never considered. Local sources are your best resource....not people half way around the world.

Tom,

as much as i have to agree with you on micro climates and where your trees are compare to vwhere they go etc. watering can be a major issue to your own micro climate.
especially here in Aus.

not knowing how your water is over in the states, but here where i am, i have two choices. rain water from a tank, that has a low ph level and has been sitting for a while. or tap water with a very high ph, fluride and hardness. i have been using the rain water tank ofcourse.
where as at my old rental house the tap water wasnt anything like this place so that was used as i didnt have a tank. anyway back to the issues at hand, watering is still quite a key to the way the tree will live, and ofcourse all other aspects of where it is positioned etc. yet due to over or underwatering i think can be a key to why we can have so many troubles yet this does come down to the local climate, the micro climate of the area and such forth.

at my old place i was finding watering had to be done every couple of days,(depending on situations) to here it is just about everyday. the thing with where i am now my trees arent protected like they were at my old place and winds have a bad habit of drying the soil out easily.

to give perspective my old place is only 10 minutes down the road. literally. less than 10 km ( approx 6 miles i think ??? )

any way this is my ramblings

jamie

Tom,

What you say is headed towards the heart of the matter. Your own micro climate does play a big factor on the health of your trees. And its something contrary to what Mr Pall is about, his statement is universal, a blanket statement, as such.

I think quality of water is a different issue, no tree is going to be healthy if the water is saline, rainwater is best, but many people have to settle for tap water.

Regards Mr Rockwell, I think he is mostly correct. I see his argument as plants, when healthy, cope remarkably well with diseases and pests. It is when they are stressed that they become targeted. At the moment I have twenty or so blackpine's recuperating after a stressful re-pot, the weak trees are plagued by mealy bugs, while the healthy actively growing trees are pest free. Same potting mix, same water, different amount of re-potting stress. But trees that have been living happily in a pot for awhile may suddenly become unwell, and people immediately look towards a disease as the culprit, yelling the mantra that you cannot over water, ignoring the fact that they may very well be doing that.

On researching this matter a while ago I came across some information regarding Oak trees, I forget which species, Oak will show no root damage after being submerged for 16 days. Oak trees in soils contaminated with phytopthora only lasted 5 days. Something about the lack lack of oxygen enabled the fungus to enter the roots. What was important was that it was a reduction of oxygen, total absence prevented the fungus from attacking the tree.

Paul

Interesting discussion,
So 63pmp, the study found that a lack of oxygen in the soil aided the spread/infection of the pathogen (phytophthora sp.) but an absence of oxygen prevented the attacks. Is this because Phytophthora are aerobic microbes, therefore, cannot live in anaerobic conditions?
I think that Phytophthora is responsible for my unhappy Casuarina seedlings, probably aided by my watering schedule!
Do you have a link to the study for us?
Thanks
P.S - Phytophthora are not actually classed as fungi as they don't have cell walls made of chitin and their spores have flagella. The endless classification debate I know, but I like fungi and these types of bastard microbial species give fungi a bad name!

63pmp wrote:Tom,

On researching this matter a while ago I came across some information regarding Oak trees, I forget which species, Oak will show no root damage after being submerged for 16 days. Oak trees in soils contaminated with phytopthora only lasted 5 days. Something about the lack lack of oxygen enabled the fungus to enter the roots. What was important was that it was a reduction of oxygen, total absence prevented the fungus from attacking the tree.

Paul

Is the problem of No Oxygen in the rootmass caused by waterlogged soil?
if the soils is comprised of very small particles ( like most soil is) and stays wet then there is no way that Oxygen can circulate around the roots. Ergo you have a problem.
If you then allow the rootball to dry out so the roots get some oxygen then the plant can very easily become stressed from lack of water as Walter describes. It becomes a very fine line to pick the right time to water, and each tree must be treated individually.
I do not have the time to do that, and with being away at work for up to 12hrs + every day, I am in no position to monitor them closely enough anyway.

I am one of the adopters of the substrate that walter mentions, and now i water everyday whether they need it or not. 1/2 hour after watering the mix is open and aerating the roots.
The only problem is that all my trainig type pots sit flat on the bench so the bottom stays for a while, almost like they are sitting in trays, but that does happen to all of them regardless of what growing medium is in the pot.

Ken

Do you instinctively reach for a spray when you have a problem, or do you consider there is something a little bit more subtle going on?

Happy to discuss this,

I have not really used any spray or insecticide before this season and I still have most of my first trees. I agree a healthy tree is generally pest free. Things don't always go to plan though and I am lucky that I have not come across issues before now.

We often put trees through alot of stress in bonsai practice such as collecting from the field and we can't always get things just right so that is when the chemicals come out to help us get it back.

Although it does not answer all my questions about the leaf curl issues I feel some of the worst affected are that way because after a heavy root pruning they went into a heavy organic mix(trying to save on fert) and the open wounds where susceptible to pathogens for too long and became infected.

With due respect to Mr. Pall and Mr. Rockwell, there opinions have little to do with trees half a world a way.

If we only listened to advice from a 1/2 hour drive radius then our techniques would stagnate as much as our over watered trees soil. I would still have to listen to the local garden expert telling me that Bonsai people only re-pot their trees in Spring so they can see that it is still alive quickly Also my pottery teacher telling me my bonsai pots are too shallow

Although you need to take the different climate into account I think it has alot to do with everyone. If we did not at least consider what the other side of the world is doing we may not have thought to use diatomite as a soil substrate.
Walter makes great points with a good substrate it is very hard to over water. This may not work for all people because of the amount of water they have or the time they have to water, even if they live next door to each other. But it is an important point no matter where you live.


It seems that many people with this trident deformed leaf at the moment are in the NSW area. Some of them are VERY experienced bonsai gardeners with advice from the most experienced in the country. If this was as simple as over watering I don't think they would be talking about it

By the varied responses soil "seems" to be the issue with water quality coming in a close second.

I assumed (perhaps bad on my part) that most were using a well draining substrate like Kens. If not, then yes you can over water if it can't escape and you keep pouring it in. However if it escapes it allows oxygen to filter in to fill the void that the escaping water leaves. Hence oxygenating the roots, promoting healthy root growth.

Jamie: I had a similar problem when living in Maryland. I lived on the shores of the Chesapeake Bay, with a well as a water source. It was not fit for man,beast nor plant ..... really nasty stuff. It was easy for us to consume water from a bottle, however that would have been an expensive proposition for the trees. So like you I collected rain water in 55 gallon drums and had one under every down spout. Worked great till we went into a cycle of drought which lasted 4 years. During this time of drought, and actually till today, I purchased an inline water purifier for about a 100 bucks which cleaned up the water to almost a neutral ph and softened the water to boot. Glad you picked up on your 10km climate change . Yep winds are nasty advisories. Had wind both on the bay and here up in the mountains of Pennsylvania. I found that to help combat the drying effect of the wind on soil that chopped sphagnum in the soil (Providing its a free draining substrate) works wonders. It holds that little bit of extra moisture that sometimes is needed when wind or work prevent you from hosing down your babies.

Paul: Your right it is a blanket statement from a guy who teaches globally, I would expect nothing different. Its a safe neutral statement that won't get him into to much trouble MArc Rockwell is an extremely intelligent fella when it comes to bonsai...for the most part, lots of experience. It goes without saying that a healthy tree will fair better than a unhealthy one .... humans are the same. Yes, re-potting can be one of the biggest stress inducing effects on a bonsai, my question is what are you doing to reduce that effect? How are you influencing your micro-climate, are you using Mycorrhiza, are you using a re-potting pre-soak treatment prior to potting...etc. Your statement about healthy trees going south is spot on with regards to people not systematically narrowing the possibilities to cause and effect.

Was this the Oak you were talking about? Willow Oak

Ken: Influence your climate! I know your using the right substrate, try amending it with a bit of chopped sphagnum to buffer the effects of work, temp and wind. I promise your trees will love it and you'll be a lil less stressed on the watering issue. Also for flat pot syndrome try elevating your pots with a 1 x 1 wood strips to get air circulation and better drainage at the bottom. I do that with all my non-authorized bonsai training containers

Brett: I think you might have missed my point.

If we only listened to advice from a 1/2 hour drive radius then our techniques would stagnate as much as our over watered trees soil.

I'm not suggesting that you go to a local farmer , or garden center shop for advise on bonsai techniques! I'm suggesting that you go to these people for basic advise on what influences Flora and Fawna and the like in your specific area, i.e. diseases, pests, etc. and how they deal with it. Most of these people have tons of experience a few even have a University degree to boot. The first important step in bonsai is knowing that good horticultural practices and how to deal with horticultural problems is not a bonsai technique. Try talking to them without using the word Bonsai (tough to do) Draw off their knowledge of plants and and what influences them locally.



I guess it boils down to being intelligently proactive in your choices to influence an optimal growing environment through observation and research

Lots of usefull advice Tom thanks for taking the trouble

Thank Tom for you suggestion re the wood

I have been trying to figure out some sensible way of doing it. the other thought I have was to cover my bench in a raised wire mesh to give them pots and airspace under them.

Might try both to see what is easier to manage

Ken

There you go Ken that would work as well. However after reading your post in my other thread I would doubt that accumulated water/ wet area is much of a problem with your inorganic mix...air flow maybe.

I'm sorry but the link to the article was on my stolen computer. It was regarding Live Oaks in Cali, research by US Forestry. I was researching oxygen demand and movement through water and was looking for a reference for oxygen demand for roots (obviously different for each species, but something that is rarely measured) the argument was about how dissolved oxygen in water could supply the needs of a bonsai tree, it was before BT collapsed. Basically I think phytophthora stopped growing "invasive tubules" in zero oxygen, but became active again as oxygen levels rose again. Soils become waterlogged for a variety of reasons, compaction from use, disrupted drainage by construction eg roads, pipelines, foundations, irrigation. The point is that something changes within the structure of a root when in low oxygen environments, some people think it is accumulation of ethylene, whatever it is, it allows pathogens in. The important thing is torecognise the signs of reduced oxygen and treat it rather then reach for the sprays.

Ken, I had high loses of Japanese maples by allowing the plastic pots to sit in puddles on a bench, I now sit mine on little tiles so they're off the deck, now they just die from drying out when I miss a watering:roll:



Extra stuff cause I've got sand in my undies,

I grow a lot of tridents, and like everyone else have problems with the leaves getting burnt. But over a few years I started to see patterns and worked out what is going on with them. (it helps having a degree in soil science and agricultural chemistry)

First of all, tridents aren't as tough as everyone makes them out to be, so they get abused. Secondly they like high oxygen levels at there roots (not as high as Japanese maples, but more then say a Zelkova). We often here about the enigmatic problem of leaf burn, and outside of the usual hot dry winds of summer, desication due to lack of water, there is no consensus as to how it happens . The fact is,Tridents will develop leaf burn as a result of low oxygen levels. There are no references for this anywhere, it is what I have observed in my garden.

The typical leaf will present as dying at the tips, and may have black dots, (This is an abused tree, chronically waterlogged, most aren't this obvious)
The way to treat it is to remove excess water after watering,
simply tilting the pot up and less frequent watering will often suffice, shove a wick up one of the drain holes if you have to. Some people repot into coarse sand, but there are reasons why this may not work, in that water would rather stay in small pores then move to big pores. So the core can still be too wet

These seedlings were starting to damp off, and really, seedtrays are hopeless for growing maple seeds in.
The leaf shows typical signs of waterlogging, the upper leaves grew after I treated the tray by tilting it.
Tilt the tray with a small pot or something, since Ive been doing this all damping off has ceased. No need for chemicals, I did not use any fungicide on these trees.

I know I'm getting a fair bit of disbelief about this, so this is the last time I'll bother mentioning it. Have a think about it anyway,

Cheers

Paul