Are we overfertilizing our plants?

[Jamie]

i think thats the best way to do it, the tree tells ya what they need generally, after all if you are taking care of them properly you will see differences, since my upping of ferts i havent seen my figs pop so hard!

jamie

[Pup]

Another subjective post!. The fertilising regime is dependent on the tree's( plants) development. In most cases when you have fern's and any( house ) plants.
They are generally developed to there potential. So fertilising for growth is not a consideration. It is purely to keep the plant health and in most cases green.

So over fertilising them would be a problem. With Bonsai in fast draining open mixes the build up of the nasties is minimal. So at re potting time they are gotten rid of with fresh soil.

When you are power feeding it is to maximise growth. So when the tree has used up the soil it is re potted so again there is fresh soil.

JMHO cheers Pup

[Graeme]

Hit the nail squarely on the head there Pup. Fertiliser programs will vary from one grower to the next. A really good program will actually vary from section to section in the same collection, whatever that collection may be. A young tree still in developement will require a totally different fert' program to a tree which is in the refinement stage of developement, which will be different again to the program required by a tree hundreds of years old. I have a mate who was horrified by the amount of fertiliser I throw at my trees and if he was to fertilise to the same degree I do, he would kill his trees because he doesn't water to my degree and his mix is much heavier than mine. There is not a lot of point feeding a tree up with a nitrogenous fertiliser if the tree is up to a maintenance stage of its developement. Imagine a 100year old fig suddenly given a handfull of Urea? Back to a years worth of defoliation to reduce leaf size again.
From my observations during the time I was teaching and judging Bonsai, I believe it would be safe to say the average Bonsai enthusiast does not fertilise enough, or perhaps more correctly does not fertilise correctly. But that is just my opinion.

[63pmp]

The point of the post was to provide a measurable, calculable, upper limit of fertilizing. It doesn't really matter what fertilizer you are using or the potting media, once your salinity (electrical conductivity) reaches a set point you will damage the plant. This point varies with the species of plant. Japanese maples sensitive, salt bush tolerant.

The initial paper was about fertilizing nursery stock in pots. It was one of the first real scientific investigations of how much fertilizer to apply to potted plants before you started over fertilizing. Nurseries use chemical fertilizers as they can tailor make their feeds depending on what the want the plant to do, e.g. grow leaves, grow flowers, extend dormancy, whatever. Now they can vary the EC of their watering solutions on a daily basis as needed as a response to sunlight.

Certainly if you don't want growth you don't superfeed your plants with nitrogen,phosphorus and potassium. You only use enough fert to keep them happy.

I suggest people get a copy and read Handrek and Black's book, Growing media for ornamental plants and turf. It gives a very good explanation on fertilizing and what can go wrong and is tailor made for growing plants in pots. (It also says that DL is an excellent addition to potting media pre-planting).

One of the problems with organic fertilizers are they are not balanced, for instance Charlie Carp has virtually no magnesium or calcium in it. Yet has a high manganese content. Prolonged fertilizing with this stuff will cause magnesium deficiencies.

Paul

[bonscythe]

I think what people are trying to say is that if you measure/monitor/calculate the individual plant's health, then there is little need to measure the upper limit of fert. If it's looking sick, don't use excessive amounts of fert till it regains health.
I don't use Charlie Carp (yet ) but from what I gather on this forum, almost everyone chucks some seasol in their scheme somewhere, which thankfully has some magnesium in it.

[Pup]

.

I suggest people get a copy and read Handrek and Black's book, Growing media for ornamental plants and turf. It gives a very good explanation on fertilizing and what can go wrong and is tailor made for growing plants in pots. (It also says that DL is an excellent addition to potting media pre-planting).

One of the problems with organic fertilizers are they are not balanced, for instance Charlie Carp has virtually no magnesium or calcium in it. Yet has a high manganese content. Prolonged fertilizing with this stuff will cause magnesium deficiencies.

Paul[/quote]

If you read the manufactures Blurb on Dynamic Lifter and have used it. You will note that Acid loving plants will suffer to some degree.

The reason for this is Dynamic Lifter does turn the Soil Alkaline. Which is not good for a lot of plants. As most plants like to be in the nuetral zone.

[63pmp]

My bad, Pup, I may have put words into MR Handrek's and Black's mouth.

The quote is

"Poultry droppings, when composted with about 45Kg gypsum/tonne, and included at a rate of 5-7.5% (by volume) into mixes, make an excellent slow-release fertilizer"

It's not quite the same as Dynamic lifter. Good call.

I don't disagree with you on DL, I just made an acute leap of logic to call it DL.

Don't let that stop you from having a good look at their book.

Paul

[Bretts]

Yep, saw that topic, 4 pages of chatter and not one reference to dangerous levels of fertilizer. This paper may be nearly 50 years old, but it is still very relevant to potted culture, and provides more information in one paragraph than in four pages of discussion.


Paul

I believe Jamie and myself discussed doing periodical testing of the soil just as your informative paragraph does. The problem we found with that was cost compared to reliable results.
It is interesting that this text has given the supposed magic number and if you have taken test results with such a device over a period of time it would be great to hear your results otherwise I don't see this as being any more beneficial than the last thread. Maybe you could even post your fertilising regime as others have. It sounds like you have it perfected!
We all know that over fertilising can cause trouble that is why we often under fertilized as we are too scared to over fertilise I think that goes without saying.

It is common knowledge that there is a peak of optimum health/growth between under and over fertilisation. The trick is finding the peak.

[Jamie]

spot on brett, and as brett said if you have testing results that would be good to see.

as for how much we are fertilizing like i said earlier i have been fertilizing on the up and up lifting it a bit every time and seeing how it goes, so far i havent had any ill effects, when i start seeing some drama i will drop a level and stick with that and see how that goes. i guess it is trial and error!


jamie

[Bretts]

You have a different climate to me there Jamie. I feel safer having a plan for the year and evaluate it as I go. I tried fertilising on the 1st and the 14Th of the month one year then every 7 days the next year now although it is hard to keep track of I go every ten days as Walter does this year which seems right so far.
Like I said in other threads the plan this year was to use balanced ferts with extra important trace elements during spring. Plus soil conditioners Back off on the Nitrogen through the hotter months and also concentrate on Autumn fertilising which I seem to get slack with every year.
I would be too scared to just keep increasing the fert until something went wrong.

[Jamie]

yea that is true brett, i am starting to get to the point where i think it is a bit OTT but i am happy they are taking in this amount, if they are taking it in and thriving then why mess with it?

just my thoughts.

jamie

[Greth]

The stuff costs money, and if most of it is simply washing thru all you are producing is highly concentrated and expensive waste water.

[anttal63]

You have a different climate to me there Jamie. I feel safer having a plan for the year and evaluate it as I go. I tried fertilising on the 1st and the 14Th of the month one year then every 7 days the next year now although it is hard to keep track of I go every ten days as Walter does this year which seems right so far.
Like I said in other threads the plan this year was to use balanced ferts with extra important trace elements during spring. Plus soil conditioners Back off on the Nitrogen through the hotter months and also concentrate on Autumn fertilising which I seem to get slack with every year.
I would be too scared to just keep increasing the fert until something went wrong.

thats a sound plan bretts; everything has a limit. yes the autumn feed is crucial. we are one of the envy's of world bonsai when it comes to having to our extended extra growing season. it would be a shame to not take full advantge of it. remember though it is still important to use low nitrogen blooming ferts last month autumn and first month of winter. ( this can vary according to your climate) for the sake of lots of budding in the next season and hardening off and thickening up.

[Bretts]

remember though it is still important to use low nitrogen blooming ferts last month autumn and first month of winter. ( this can vary according to your climate) for the sake of lots of budding in the next season and hardening off and thickening up.

There seems to be some debate here Antonio. There has been some argument put forward that there is no reason to change the ratio to suit the season. It seems reasonable that we need to ensure that there is plenty of P+K at that time of year but some argue that there is no real need to drop the nitrogen levels. Saying the tree will use what it needs and the rest will be flushed away. There seems to be no proof that nitrogen will promote growth into the colder months?

[anttal63]

sorry bretts no scientific proof here, just a whole bunch of happy trees all year round. each to their own,