AusBonsai

I was at B*********ngs today and was looking at the Osmocote range of slow release plant foods for things like, Azaleas, Roses, Aust. Natives and the general plant food. I was always under the impression that the main factor responsible for growth out of Nitrogen, Potassium and Phosphorous was Nitrogen. Yet, I noticed that out of all the plant foods mentioned above, the one with the most Nitrogen was the one for Natives at 17%. (I thought natives did not require such a high concentration, in fact I thought it would have the lowest ratio of Nitrogen) In any case, if I applied a slow release with 17% Nitrogen, 1.6% Phosphorous, and 8.7% Potassium on a Chinese Elm or a Serisssa, am I likely to accelerate it's growth or kill it?

Cheers Guys

Hi Jester,
I have heard of some Banksia and Hakea spp. having a sensitivity to high phosphorus levels but don't know if there's any with a nitrogen issue
I have been using the osmocote native with basically all of my plants, including a few elms and a maple with what seems to be nice healthy growth, the internode length might be an issue I suppose but it's what I bought at the time and it seems to be fine for now.
Don't know if that helps you at all...
Why is it that you think it might kill your elm(s)?

Hi Bonscythe and thanks for your response. Up until now, I have been using dynamic lifter pellets on all my Bonsai. It has a very low Nitrogen ratio of (from memory) about 4-6% , although I also use Dynamic Lifter liquid as well which has about 10% Nitrogen. I guess that with a fertiliser that has 17% Nitrogen, I may run the risk of burning my Bonsai as they are not used to it (I don't know). Having said that, I am doing everything I can to accelerate their growth. If this means changing their feeding regime, I am willing to try. I am trying to take every advantage of Spring whilst it's here.

Cheers

John

That level of nitrogen should be fine for everything. High nitrogen is great for plants you are thickening up. Not so good for finished trees. It will be difficult to wire (due to it cutting in quickly) and pretty difficult to get nice ramification, small internodes and leaf reduction with high levels of nitrogen. The nitrogen is what makes the leaves green. It is used in the chloroplasts to turn light into food. However, too much will burn the roots.

JayC

Thanks very much Jayc

Incidentally, do any of you know which commercial available plant food has the highest ratio of nitrogen? Can't be much more than 20% can it?

Hi john, the osmocote only releases a small amount of nitrogen over a period of time, as does the dynamic lifter pellets so i beleive, so to me then it cannot be overdone and thefore wont burn the roots. Someone correct me if im wrong.

For high nitrogen I am pretty sure all of the tomato ferts are the highest, but don't hold me to that!

I was looking at the range of slow release Osmocote fertilisers too and i was wondering something similar.
however mine would be worded a lot less scientifically! 'Should I be using the natives osmocote for all my bonsai incl. exotics, because of the low phosphorus level, or if phosphorus actually benefits my exotic trees' is along the lines of what I was wondering.

I'd love an answer

However, on your question, I'm unsure whether it would greatly benefit either of your trees.
But i very highly doubt it would 'Kill' either of those trees, i'm not sure how fussy your Serissa is, but elms are tough little trees try it for a while, and see if you can notice a difference to when you were using your other fertilisers.

or even use a mix 1:1 of your Safe - trees and shrubs Osmocote with Experimental - Natives Osmocote so the effect of the nitrogen isn't as much of a problem if you truly believe it might kill it

I'd love to hear the results of the little experiment! and I'm sure I'm not the only one

urea highest source of nitrogen .

G,day Jester. I use two Chemical fertiliser's. Both are obtainable though most hardware and general nurseries

For my exotics I use Phostrogen general purpose has an NPK ratio of 14%N, 4% P, 28% K

Miraclegro for azaleas and camellias. The NPK in that is N 28% P 1.8% K 10%

All other percentages are made up of the required micro elements.

I have found that this is a good one as most ( most ) natives like an acid soil.

I do alternate the fertilser's. I use Miraclegro once per month. I use Phostrogen one per fortnight. I have used this formula on my tre's for as long as I have been growing them.

I give all of my tree's a treatment of complete trace elements once every 6 months as constant watering does tend to leach the soil of them.
It has worked for me for over 20 years. Pup

the complete trace elements that are needed, can these be bought as a seperate fert. as such???
i use miracle gro all the time, feed like crazy though out the growing period, once a week at half the recommended level. it seems to work great for me.
my climate here might allow me to do that though aswell so it could be different for your area!

Yes you buy it as complete trace elements. It is water soluble. What you will find is Shimpaku juniper do not like high Nitrogen.

They do respond well to Dolomite lime which can also be purchased from garden centres and hardware stores.
I usually add one match box full of dolomite to 10 litres of soil mix. For junipers. Pup

How much of the complete trace elements should someone pot on a bonsai pot? The powder type. Can you put too much?

I was told to cover my pots soil with an inch layer of dolomite as it made the roots grow As usual I was gun ho as it came from a very reliable source. The dolomite I had was a fine powder so it instantly clogged my soil and I had to repot everything the next spring.
The very intresting thing is that an amur maple root over rock I was growing out in a colinader did not get repotted and the following season no matter what fertilieser I used I could not get rid of a nutrient deficency. The leaves where a constant web of green over yellow and it grew bugger all.
I got around to bare rooting it this spring as was very suprised to see alot of root growth even though the top had grown bugger all.
Also as the tree leafed out this spring it still had the nutrient deficiancy. The newest set of leaves seems to be heading back to normal so I guess it was still running of last seasons nutrients.
I am taking it to display this weekend at Cowra and I am expecting alot of hey that's got a nutrient deficency from the experienced and lots of oh that looks so cute from the less knowlagable