Question on Fertilzer strength

[thegreenhand]

I know that different species of plants and trees will prefer varying levels of nutrient strength, but I'm wondering if there is a rule of thumb with bonsai in particular. For example, should EC or pmm be lower than a full size tree because of the larger number of fine roots near the surface?

I've read varying suggestions about feeding according to labels; some say follow them, others say half strength or feeding "weakly weekly".

Just wondering if anyone is testing their fert strength and what kinda numbers they shoot for with different groups of trees.

Thanks in advance!

 

[jk_lewis]

Expect answers that are all over the map. I'm of the read-the-label school.

 

[DougB]

Some will say just feed and tree will use what it needs. Others say it depends on species, soil composition, time of year, health of tree............. and the list goes on. Best answer is talk to local folks and then begin to develop your own regiment.

 

[Dav4]

I am in the "the tree uses what it needs" crowd. Most of my trees are in development and are kept in 100% inorganic soli, though some are in mostly composted bark/soil conditioner...I use full 20-20-20 strength Miracle Gro and Fish emulsion watered in every 7-10 days during the growing season. My more refined trees get tea bags filled with Plantone during the year, with less frequent applications of the liquid feeds.

 

[Paradox]

There seems to be some varying opinions depending on which species we are talking about. There is also varying opinions depending on time of year both in general and by species. There are also differences with what stage of development the tree is in. There is no one size fits all with bonsai and and fertilizer.

Some people use only organic, some use chemical. Some use full strength, others use half strength. Timing of application also varies.

I suggest you do some reading, there is plenty of info and threads here and elsewherejust about fertilizer, and decide for yourself what works best for you.

Sorry I cant be more specific, but there really is a very wide range of options that are too long to list.


I use an application of miracle grow 10-10-10 granules in early spring then every month I mix miracle grow powder and half the concentration. I do vary applications for some species in terms of timing (ie: azaleas get fed in early spring then not again until after blooming). All of my trees are in the development stage. For "finished" trees, I would reduce the amounts. The azaleas get hollytone instead of miracle grow. I am also looking a ironite as a spurce of fertilizer because Ive heard good things about it and it provides some additional micro nutrients. I apply the granules/first application in April and stop fertilizing after September.

 

[M. Frary]

I use miracle go twice the strength recommended every Sunday till the leaves fall off. I used to put it on 5 times the amount prescribed but felt all I was doing was wasting fertinizer.

 

[Skinnygoomba]

Mike, what kind of soil do you use in combination with that routine?

In reading Walter Pall's stuff on this topic he made mention many times that to use one piece of his advice would require the other two pieces. Meaning that if you fertilize heavily, you would also need to use in-organics and also water much more often.

I feel as if most of my plants are in training, so I'm slowly working toward being in mostly in-organics which allows me to fertilize more heavily and requires watering more often. I dont have enough experience with my routine to know where 'too much' is just yet, but I'm slowly working toward it.

 

[thegreenhand]

Thank you everyone for the replies and suggestions, however I'm not really asking for a specific formula or even NPK ratios of feeding regiments.

I'm just curious if anyone tests their juice with a PPM meter.

I'm really curious, too, now that Mike said he used it at 5x label strength, which I'd have to imagine is at least 3,000+ppm.

For reference I use well water that tests at 150ppm, and for plants like my orchids I feed a very weak strength fertilizer that tests out to 500ppm. If the fert mix is too strong it'll burn the foliage and start dropping buds on my flowers, I'm thinking maybe this isn't the case with trees in general and that's why the strength of the mix is not of the highest priority?

 

[Cadillactaste]

I use miracle go twice the strength recommended every Sunday till the leaves fall off. I used to put it on 5 times the amount prescribed but felt all I was doing was wasting fertinizer.

Mike...I thought of your post as I read a topic of root burn. Where osmosis is reversed when excess fertilizers are used. Glad you've not experienced this...but something to maybe read up on...so you know the signs.

 

[GrimLore]

Mike...I thought of your post as I read a topic of root burn. Where osmosis is reversed when excess fertilizers are used. Glad you've not experienced this...but something to maybe read up on...so you know the signs.

In non-organic fast draining mixes I often use up 5 - 7 and sometimes 10 times the dose. Reason is daily multiple waterings... This season I went with Jacks Professional 20-20-20 with micronutrients and all went well.

Grimmy

 

[Cadillactaste]

In non-organic fast draining mixes I often use up 5 - 7 and sometimes 10 times the dose. Reason is daily multiple waterings... This season I went with Jacks Professional 20-20-20 with micronutrients and all went well.

Grimmy

Well...it's interesting we now have two members of the same belief of stronger fertilizer yet sees no issues...curious what substrate the author was mentioning...that would cause that then with bonsai?

I always thought if you over fertilized you were creating a tree on steroids basically...that something would weaken it's overall make up. But...never read anything on it. Just my gerbil spinning on it's wheel.

 

[jk_lewis]

But that's where the trees-use-what-they-need school of thought rule the day. The bulk of that 5-10X load of coins you pour into the soil flows right straight out the drainage hole.

Peeples needs to think!

READ THE LABEL.

The tree will STILL use what it needs, because the label instructions are for either ground application or application to more organic soil, and NOT in Bonsai pots or soil.

Every Sunday?

Our goal in bonsai is not LOTS of leaves. It is healthy trees.

I fertilize everyone three times a summer. Period. Been doing that for nearly 40 years and my trees don't complain. They flower, fruit, grow green leaves, have good fall color. They're happy.

Seems I sure was right about answers being all over the map.

 

[Cadillactaste]

But that's where the trees-use-what-they-need school of thought rule the day. The bulk of that 5-10X load of coins you pour into the soil flows right straight out the drainage hole.

Peeples needs to think!

READ THE LABEL.

The tree will STILL use what it needs, because the label instructions are for either ground application or application to more organic soil, and NOT in Bonsai pots or soil.

Every Sunday?

Our goal in bonsai is not LOTS of leaves. It is healthy trees.

I fertilize everyone three times a summer. Period. Been doing that for nearly 40 years and my trees don't complain. They flower, fruit, grow green leaves, have good fall color. They're happy.

Seems I sure was right about answers being all over the map.

Fertilizing falls under substrate mixes...as to what ones find works for them. I must say...I am impressed you fertilize just the three times yet have happy trees. It is such a broad spectrum of what ones find works for them.

 

[Victrinia Ridgeway]

But that's where the trees-use-what-they-need school of thought rule the day. The bulk of that 5-10X load of coins you pour into the soil flows right straight out the drainage hole.

Peeples needs to think!

READ THE LABEL.

The tree will STILL use what it needs, because the label instructions are for either ground application or application to more organic soil, and NOT in Bonsai pots or soil.

Every Sunday?

Our goal in bonsai is not LOTS of leaves. It is healthy trees.

I fertilize everyone three times a summer. Period. Been doing that for nearly 40 years and my trees don't complain. They flower, fruit, grow green leaves, have good fall color. They're happy.

Seems I sure was right about answers being all over the map.

Even more... it has to do with the level of refinement on the tree.... gods know I would not fert most of my trees to that extent. The ones which need extra get surfaces ferts that leech in with watering. But to feed super strength to some of my refined trees would destroy the image in a season.... and what's the point of that?

If you have a lot of babies... it doesn't rightly matter... the more advanced the tree.... the more it matters.

V

 

[GrimLore]

Even more... it has to do with the level of refinement on the tree.... gods know I would not fert most of my trees to that extent. The ones which need extra get surfaces ferts that leech in with watering. But to feed super strength to some of my refined trees would destroy the image in a season.... and what's the point of that?

If you have a lot of babies... it doesn't rightly matter... the more advanced the tree.... the more it matters.

V

For the record(not argument) Walter Pall and others do far more then I do and I do not see a lot wrong with his trees. The trick "for me" is balancing the substrate, plant and timing along with dose. Walter has a "one for all and all for one" which I do not see a need for not having as much to take care of. Either way the basic concept I am referring to is Modern Substrate/Modern Fertilizer and although it may not work well for you I do have the time and probably far less stock as MANY do here.

Grimmy

 

[KennedyMarx]

Seems that a general rule of thumb is:

Inorganic soil mix = organic fertilizer
Organic soil mix. = chemical fertilizer

The more freely your soil drains the more water it gets. The increased watering flushes the excess fertilizer and salts out of the pot. This is (at least partially) why people use fertilizer cakes on the soil surface of plants in inorganic Japanese style soil mixes. The organic cakes have lower NPK ratings compared to the typical chemical stuff, but usually you use more cakes and excessive cake use won't burn the roots.

 

[coh]

Quoting from Brent Walston's article on fertilizing:

To achieve a concentration capable of doing this ("burning" roots) requires mixing a batch many times stronger than recommended full strength soluble fertilizer. Usually you will see it only if too much solid fertilizer is directly applied to the soil surface or in the case of very hard water.

The fact that Walter Pall uses such high concentrations tells me that it is not easy at all to "burn" roots when using liquid fertilizers.

I haven't figured out the optimum amount to use for my growing conditions. Actually, I think I've been systematically under fertilizing for a couple of years, based on plant growth rates and appearance. So I'll be upping the amounts quite a bit next year and we'll see what happens. At this point I'm willing to risk some leaf disfigurement to get things growing at a better rate.

Chris

 

[Vin]

Expect answers that are all over the map. I'm of the read-the-label school.

Carnac the Magnificent says you're correct

 

[63pmp]

You are better off using micro Siemens per centimetre (uS/cm) when talking about salinity, rather than ppm. This is because ppm from a conductivity meter is an approximation only.

Japanese maples and Japanese Beech would be the most salt intolerant plants used in Bonsai, though not the only ones. I try and keep the salinity of my irrigation water to below 750 uS/cm. 1250 is about their maximum, but its dependent on temperature.

Plants will tolerate high spikes of salinity, but only if the salts are leach out relatively quickly. Which is how people get away with Walters fertilizer scheme.

Very unlikely you will get a proper discussion about fertilizer, EC or pH here, sorry, its just the nature of this forum.

Paul

 

[Shima]

The fact that Walter Pall uses such high concentrations tells me that it is not easy at all to "burn" roots when using liquid fertilizers.

Chris

It's VERY easy to burn roots with liquid fert if the substrate is not open and fast draining.