Repotting and Fertilizer

[Webos]

The norm is to start fertilizing around 6 weeks after repotting. But what if we found the tree to not have developed its roots as much as we had anticipated and repotted it into a different soil type without cutting any roots?

Would we begin the feeding regime immediately? Wait 6 weeks? Or wait just a few weeks?

[Jamie]

good question mate

im not completly sure, if it was me i would wait at least a few weeks as even though you dont cut the roots you have still disturbed them some what and i think the tree would want a "settling" in perion for this. i have found certain faster growing species like figs (up here anyway) can be readily fed after a root prune in less than 6 weeks, by then they have settled in the pots and are pushing a lot of energy in all directions so when i see that is when i decide to feed, it usually takes about 3-4 weeks here in QLD for me to see this sort of result.


jamie

[anttal63]

if ya go by the text; if pushing growth its ready to take up fert. im only careful with the trees that seem to sook otherwise i fert pretty much straight away.

[Bretts]

I think if the tree looks like it could use some fertiliser, ie starting to grow strongly, then I will start to fertilise. I just don't believe fertiliser used in the normal way burns fresh roots. A healthy tree always has fresh roots.
I do think it is a good idea to make the tree look for some nutrients before you hand them over on a platter though

[BoNZai]

Hi guys,

I don't think there is a hard fast rule for using fert after repotting. Personally I feel that a plant will take up any fertilizer when it has produced new active roots and that is obviously some time after repotting. It will depend on the species, some will be quicker then others.

I normally wait untill I can see some new top growth on the tree before I use fert after repotting. At that point I know the tree is active and will start producing new roots. Any fert used prior to that seems to me simply wasted as there are no new roots to use it.

Root burn is normally the result of using Nitrogenous fert in too higher doses, not nessecary starting fertilising too early.

So, recapping, start fert after some top growth appears in small doses and ramp it up as top growth increases. Remember, the more top growth the more the plant will photo synthesise, the more it can use fert and of cause water.

Hope this helps

BoNZai

[Deemon]

http://www.evergreengardenworks.com/fertiliz.htm

Interesting reading, if you have not read this.....you should. Very interesting.

[Bretts]

I had read most of that before Deemon but I did not remember reading this that literates my thoughts that Fertiliser does not burn new roots.
There are many out there still sticking to teh wait 6-8 weeks theory.

Fertilizing Sick Plants
Another common bonsai myth is that sick or recovering plants, or newly transplanted bonsai should not be fertilized. The analogy is that it will over feed the patient or is the equivalent of over dosing with vitamins. I think the proper analogy should be that feeding at half strength or not all is analogous to not taking your medicine, vitamins and nutrition when you are sick.

The recommended strength is designed to produce a soil solution of fertilizer salts at a specific range of electrical conductivity. In this range it is very easy for plants to pick up the various N,P, and K ions. It doesn't matter if the plant is a seedling, newly rooted cutting, newly root pruned bonsai, or recovering plant. They all will pick up nutrients more easily if fed in this range.

Roots are roots. Probably the most tender roots you will ever come across are the newly formed adventitious roots on a cutting. These are very fleshy and extremely fragile. I have fertilized my newly rooted cuttings (and seedlings) for years with full strength soluble fertilizers and they have all thrived. In fact, they quickly show chlorosis if I don't feed them at this level.

My theory to hold of a bit to make them look for fertiliser (such as osmacote in the soil when repotting) may also be un-nesacary by this advice?

[Deemon]

Yeah, Agreed.

I've read most of Brents articles and came to the conclusion that he knows a little about bonsai

Very good reading.

[stymie]

I venture to reproduce an article on the subject, which I wrote for a UK site. Oz readers would need to subtract six months from my schedules. Our temperatures are vastly different and that would have an effect on feeding practices. My own method is to feed weakly but often. Many of my trees are mature and have slowed down considerably in their growth. I also favour non-organic planting mediums.

Feeding
FERTILIZATION

The major nutrients are obtained by plants from water, air and sunshine. Trees getting these three sources will survive. The daily watering routine in an open planting medium pushes stale air out of the planting medium and draws fresh air in behind the water as it moves downwards. When they have a restricted root run as in a bonsai pot, other foods have to be provided for optimum health and rejuvenation.

The root system uses up the store of food in the small volume available to it more rapidly than if it had an unrestricted volume to reach through in search of its needs. Furthermore, the water which escapes through the drain holes in the pot, takes with it some of the dissolved food. The amount of these nutrients in the medium at re-potting time is mostly used up within a month when the plant/tree is actively growing. The answer is to replace these nutrients after the passage of a month.

The nutrients in highest proportion according to need are; nitrogen (N), phosphates (P) and potash (K).
Manufacturers of proprietary brands of fertilizer are required to list these items in this same order NPK as ingredients. Nitrogen is used by the plant to extend growth of buds leaves and twigs. Phosphates are mainly used up in root growth and potash in the formation of flowers and fruits. Other elements are added in smaller quantities to fertilizers during manufacture. These include calcium, sulphur, iron, zinc, copper, molybdenum , sodium and some other traces, even vitamin 'B'. These vary from brand to brand and are sometimes absent from the cheaper products.

A balanced fertilizer is one which has fairly equal percentages of the main three ingredients NPK and which would be labelled 10:10:10 or 5:5:5. This is what we would mostly use for our potted plants/trees during the main growing period from March to Mid-September. After that, as the cooler weather approaches, growth slows down and hardly any nitrogen is used, also, the current year’s growth needs to be hardened to withstand winter temperatures. This can be achieved by using a formula ratio of 0:10:15 or other low N high K combinations which are often found in tomato fertilizers. When people make up their own fertilizer, they can include the trace elements by adding a pinch of frit which is made for the purpose. Another ingredient which has become popular recently is humate, a residual from the decomposition of organic substances over a long period.

Growers will adopt a fertilizer of their own choice which fits in with their management routine. Pelleted, powder, liquid and cake forms are available.
My own routine is to use a liquid feed at fortnightly intervals from the end of March to late October. Specimens of this type include Phostrogen, Miracle-gro and B and Q powders which are dissolved in water before use. All these products have varied formulae to fit in with the requirements of the paragraph above.

Plants with various degrees of lime intolerance, namely ericas, azaleas and some needle trees are better catered for by an ericaceous formula, which increases the acidity of the planting medium. In other words reduces the ph value.
An off-white powdery residue at the base of a tree’s trunk or on the top, inside edges of the pot are often an indication that the ph has risen and deposits of lime salts are being left behind. These can be avoided by the use of one of the ericaceous fertilizers, chelated iron or even a drink of black tea on occasion.

If leaves display yellow patches in the middle, it may be an indication of a deficiency which can usually be corrected by watering with a solution of epsom salts - 1 teaspoonful to a pint of water usually does it for me. Some people use this on a routine basis at two to three month intervals whether or not it seems to be necessary. It does no harm anyway.

Plants/trees which are kept indoors during the winter continue to grow at a reduced rate and should be fed with a half strength solution at monthly intervals only.

Contra indications.

Do not fertilize medium which has dried out. Water well before application.
Do not fertilize weak or sickly plants/trees which would be unable to utilise it.
Do not fertilize within one month of re-potting or root pruning. (risk of damaging root tips)
Do not fertilize deciduous varieties in Spring until signs of growth are observed.
Do not use a stronger mix than recommended, rather err on the side of higher dilution.

Plant nutrients.

Magnesium.
This is the central constituent of chlorophyll and helps plant enzymes to do their jobs. New chlorophyll cannot be manufactured without it so a shortage causes colour loss on the leaves starting from the insides and spreading outward. Not nice to see yellow in the middle of the leaves, or even white in the case of severe deficiency. Along with calcium, nitrogen and sulphur it is also active in making protein to create cells and allow growth to take place.
Loss of chlorophyll in the middle of leaves, particularly the older ones, is the sign that supplementation is needed. A dilute solution of Epsom salts sprayed onto the leaves is readily absorbed and corrects the shortage very quickly indeed.
As a measure to avoid a shortage, I have added a little to my water two or three times during the growing season. If there are any adverse effects from a surfeit of Magnesium, I have not experienced any.

Nitrogen.
Vital in regeneration and growth, being an essential part of the amino acids, which combine to make proteins, the building blocks. A shortage may be caused by a lack of bacteria which fix it in the medium, excessive leaching by heavy rainfall on very open mediums or failure to fertilize a sterile medium such as Akadama alone. The symptoms of a shortage are; slow or stunted growth, older leaves turning yellow and reddening of the leaf petioles and veins. The normal bonsai procedure of feeding at fortnightly intervals with half strength balanced fertilizer during growth periods is adequate insurance against a deficiency of this essential nutrient.

Phosphorus.
Links together with fats and oils to make cell walls, which are capable of allowing the passage of moisture and nutrients into the interior. It is active in chromosome formation and photosynthesis. It acts like a programme driver in a software package, determining the amount of various foods and minerals to be taken in by the roots to create a correct balance. Root and bud growth, leaf colouration and maturing of tissues are controlled by this wonder constituent. As it helps to make chromosomes, a dearth means that genetic material is not formed so fruiting is stopped, along with the manufacture of new cell walls and growth regulators. Like nitrates, it is absolutely necessary.
A slight bonus from a low level might be better autumn colour.

Calcium.
Puts the ‘bones’ into the twigs and branches in the form of stiffening membranes in the cells. It also helps to control membrane permeability, (Mentioned in the first sentence in phosphorus above). Like a ‘bouncer’ it decides which elements to let into the cells. Even ericaceous, (lime hating), plants need some of this. A complete absence would result in rotting margins in new leaves, no buds and die back of root and shoot growth points.

Sulphur.
Works along with nitrogen etc. by actually linking the amino acids together to make building blocks. Like a lack of nitrogen, insufficient sulphur results in yellowing of leaves but this time the younger ones.

Oxygen.
Being essential to most living things, it is needed round the roots as well as the leaves, hence the open, porous, planting mediums which are so beloved of bonsai. These allow the passage of air behind the draining of water, which also contains oxygen. It also has a structural role and controls the use of energy which allows the roots and leaves to work.

Potassium.
It nips in and out of cells to control the amount of water in the plant tissues, keeping everything turgid and under pressure. Also the action of stomata is regulated by this policeman to balance fluid losses. It controls the operation of enzymes, which make protein although it doesn’t actually do any building itself.

There are other elements, which are only used in tiny amounts, such as boron, chlorine, copper, iron, manganese and molybdenum.

_________________
Regards from Stymie.
My name is Don and I'm a bonsaiholic.

[Jonden]

Thanks Stymie,
Avery interesting and concise article that explains fertilisers and how they work in a very easy to understand format, great work.
Cheers, Jonden

[Bretts]

Yes thanks Stymie but the problem is it condradicts Brent Waltsons

interesting and concise article that explains fertilisers and how they work in a very easy to understand format,

One of the articles must be wrong to some degree?

[Pup]

Yes thanks Stymie but the problem is it condradicts Brent Waltsons

interesting and concise article that explains fertilisers and how they work in a very easy to understand format,

One of the articles must be wrong to some degree?

The thing is we all have opinions, When I read something I try it first, then if it works great if it does not say so.

This is a problem that will never be solved because. We all have opinions. Mine for what its worth. Depends on what fertiliser you are using.
Solid organic or chemical solid or liquids. Both solid fertilizers need about 4 weeks before the plant will get any. Liquid and the plant gets it straight away.

A guy I know grows Fuchsias. He treat's them like Bonsai. He re pots them like we do. What he does that I have since tried to no ill affect is.
Straight after re potting he feeds with what he considers a low Nitrogen fertiliser. What was a surprise was he used Phostrogen. Then 6 weeks after he starts using high nitrogen fertilizers. He has prize winning Fuchsias.

As I said try these before you condemn them. As I said JMHO cheers Pup

[Bretts]

When I first began I held of fertilising for 6 weeks as was recommended to me. I found that I was in the heat of Summer by the time that period was over.
I have experimented with strong doses(slightly over recommended dilution) of fertiliser straight after heavy root pruning to no ill affect. I started to question the idea that the new roots where susceptible to burn from fertiliser as I figured they are always growing so what is the difference.

I find Brents comment in his article.

Roots are roots. Probably the most tender roots you will ever come across are the newly formed adventitious roots on a cutting. These are very fleshy and extremely fragile. I have fertilized my newly rooted cuttings (and seedlings) for years with full strength soluble fertilizers and they have all thrived. In fact, they quickly show chlorosis if I don't feed them at this level.

The issue is we often get conflicting advice from people that have done these things and we must try and work out which is correct and why both ways seem to work! it is hard to argue with the above comment from some one who has done this extensively. So maybe it has something to do with the high organic soils that we used to use and that they already had a high volume of nitrates in them so adding extra before they leached out caused issues?
Deborah Korreshoff recommends no fertiliser in the first year but she had high organic soils when the book was written.
So my theory is that people have had issues with fertiliser after re potting not because fresh roots can not handle normal amounts of fertiliser but because adding extra fert to a fresh fertile soil causes an abundance of nitrates that is unhealthy for any normal tree!
Some of my trees got a very fertile mix this year experimenting with Deborah's old way and I think this thinking has given me the answer why some small hornbeam seedlings are showing what may well be the effects of too many nitrates. Fertilising an already very fertile soil