Urea fertilizer - outstanding results

Advertise with us
shop deals on amazon
Shop deals on ebay
Slippertalk Orchid Forum

Help Support Slippertalk Orchid Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
gonewild said:
If the members of your club all have the same problem with nitrate fertilizer having only yellow leaves then look at what you all have in common. What forms of nitrate are you using? Are you sure you are using fertilizer with a high ratio of nitrate compared to ammonia? Are you all using the same nitrate source?
Click to expand...
All are using a copy of MSU (Akerne RainMix) made by a local nursery (Akerne - Antwerpen Belgium).
It is a full nitrate fertilyser. A few members have trumpeted that it does not work at all for the Masdevallias.
 
Brabantia said:
All are using a copy of MSU (Akerne RainMix) made by a local nursery (Akerne - Antwerpen Belgium).
It is a full nitrate fertilyser. A few members have trumpeted that it does not work at all for the Masdevallias.
Click to expand...

I've been using this for around 5 years now along with a good friend of mine in the UK. Since changing from the available products in the UK, both our plant collections have improved massively in every way, growth, blooms, roots etc. This has resulted in our awards as the plants have been entered at shows and judged. I mainly have a multifloral paph collection and my friend has a very large collection of masdevallia! He also has a few other species including vanda, dendrobium etc and they all get the same treatment. The results speak for themselves. I will admit that I do experiment and am always looking for ways to improve hence why I've also got k-lite and often use a workaround which involves adding calcium nitrate and magnesium sulphate to the Akerne with amended amounts. I have monitored and get varied results but I'm happy with what all 3 provide. My only concern was a slightly paler colour hence the possibility that I may incorporate another local feed at various amended dilutions at spontaneous intervals. This is our Miracle Gro water soluble lawn food @ 30.6.6. Link on further details are

http://www.gardendirect.co.uk/garde...s-killers/miracle-gro-water-soluble-lawn-food

Gary
UK
 
Stone said:
Man you really get excited Lance....Chill dude

Nothing you have ever written, posted or shown has benefited my orchid growing but I still read your posts for the fun. You put out question after question that leades nowhere. The published proof was provided by polyantha. Go back and see. In his case Urea was better than nitrate.
Click to expand...

I'll pass on commenting on your personal insult all this does is drag down the quality of this forum.

If you can't reply with constructive informative input please refrain from commenting on my posts.

Polyantha did not publish "proof". At least not based on how you have defined proof in your previous posts.
 
Stone said:
I have used it but stopped because ther were too many preciptates forming. They should never put Cal nitrate together with the sulphates and Phosphates!!! (which they do!)
Always mix your Cal nitrate seperately then add it to the FINAL solution when completely diluted.

One of these days I'm going to manufacture and market a fertilizer which I actually like. :evil: But its gotta be a 2 part no question!
Click to expand...

thanks for the insight.
 
Brabantia said:
All are using a copy of MSU (Akerne RainMix) made by a local nursery (Akerne - Antwerpen Belgium).
It is a full nitrate fertilyser. A few members have trumpeted that it does not work at all for the Masdevallias.
Click to expand...

The problem is probably pH related.
Do you know the pH of your water and media?

Basically....
The type of nitrogen has more of a direct effect on the growing environment than on the plant itself. As plants absorb nitrate the media pH increases and as they absorb ammonia the pH decreases. So if your water and media pH is tending on the high side of the scale using pure nitrate nitrogen will move the pH higher to a point where the plants can't take up enough nutrients. Balance this by using both nitrates and ammonia nitrogen at the same time.

Using pure ammonia nitrogen works the same in the opposite pH direction. UREA results as ammonia nitrogen. The major difference when using pure ammonia nitrogen and having the pH moved lower is that at low pH levels ammonia is toxic to plant tissue.

When nitrates cause the pH to rise and a problem is created the plant simply stops getting food and turns yellow and does not grow.
When ammonia causes the pH to lower and a problem is created the plant tissue can (is) be permanently damaged. That is why 100% UREA based nitrogen is not advised to be used constantly for orchids.

Ever wonder why your plants roots rotted and the top looks fine?
Ammonia in the soil kills roots and Ammonia (UREA) as foliar feed keeps the foliage alive all at the same time! But that is a different subject.
 
gonewild said:
The problem is probably pH related.
Do you know the pH of your water and media?

Basically....
The type of nitrogen has more of a direct effect on the growing environment than on the plant itself. As plants absorb nitrate the media pH increases and as they absorb ammonia the pH decreases. So if your water and media pH is tending on the high side of the scale using pure nitrate nitrogen will move the pH higher to a point where the plants can't take up enough nutrients. Balance this by using both nitrates and ammonia nitrogen at the same time.

Using pure ammonia nitrogen works the same in the opposite pH direction. UREA results as ammonia nitrogen. The major difference when using pure ammonia nitrogen and having the pH moved lower is that at low pH levels ammonia is toxic to plant tissue.

When nitrates cause the pH to rise and a problem is created the plant simply stops getting food and turns yellow and does not grow.
When ammonia causes the pH to lower and a problem is created the plant tissue can (is) be permanently damaged. That is why 100% UREA based nitrogen is not advised to be used constantly for orchids.

Ever wonder why your plants roots rotted and the top looks fine?
Ammonia in the soil kills roots and Ammonia (UREA) as foliar feed keeps the foliage alive all at the same time! But that is a different subject.
Click to expand...

I am of the opinion that soil and orchid potting mixes are not the same and that we therefore should be careful about transferring conclusions from soil to orchid potting mixes.

Basically, if we look at the chemistry, urea in aqueous solution transforms to ammonia and carbon dioxide. Which itself could react to ammonium carbonate. There would be a surplus of ammonia though as each urea may react with one water to give two ammonia plus one carbon dioxide.

Depending on pH this ammonia gets converted to ammonium and this reaction is reversible. At high pH (around pH=8?) the ammonia gets to toxic levels. As such, the ammonia is increasing the pH by "stealing" acid(H+) from the substrate in the transformation to ammonium. Normally the pH of the substrate is low (5.5?) and acid enough to take care of any ammonia that is liberated..

If the ammonia gets too plentiful, free ammonia will skyrocket pH and become toxic. This is normally not the situation since the ammonia is liberated slowly and the urea addition is not that large. Well, perhaps some of the feedings at 250ppm N could have that potential....

What happens to the ammonium that is produced from the ammonia (while acid is consumed)?
Some is going into the velamen and is absorbed by the plant while some acid is given off by the plant, and some gets adsorbed on negative sites on colloids and other charged surfaces. This ammonium may then become oxidised to nitrate which is either flushed out or taken up by the plant that will liberate an OH group per nitrate consumed.
Looking discretely at the processes in the root-zone will give the impression that ammonium gives lower pH while nitrate increases pH but it is not that simple as I have tried to explain above (ammonia eats acid while converting to ammonium).
Additional to the charge transfer in connection to the uptake by the root, other processes run in parallell liberating or consuming acid. If you take the gross reaction of the decomposition of urea, disregarding loss of either ammonia or carbon dioxide, the pH should increase because of the transformation of ammonia to ammonium, but decrease again if the ammonium gets consumed by the plant.

just my twopence:sob:
 
Bjorn said:
I am of the opinion that soil and orchid potting mixes are not the same and that we therefore should be careful about transferring conclusions from soil to orchid potting mixes.
Click to expand...

Agree. Take notice that I refer to "soil less media" in order to clarify conclusions. Also I want to point out that most of the info that I posted links to declare that soil less media is more sensitive the the ammonia than soil.

Normally the pH of the substrate is low (5.5?) and acid enough to take care of any ammonia that is liberated..
Click to expand...

Let's define normally. Growing in bark heavy media the pH will be as you say (5.5?).
What about non bark media heavy in leca, diatomite, limestone, perilite, pumice, carbon, CHC, ect? Some Leca media comes as pH9!
What about the effect liquid fertilizer has when applied directly to areal roots?

I think maybe there is no normal orchid media and that is what makes it hard to have a standard pre made fertilizer formula that works for everyone. But if the pH is considered maybe that becomes the standard point to find what "normal" is to base the nutrient decision on.

Additional to the charge transfer in connection to the uptake by the root, other processes run in parallell liberating or consuming acid. If you take the gross reaction of the decomposition of urea, disregarding loss of either ammonia or carbon dioxide, the pH should increase because of the transformation of ammonia to ammonium, but decrease again if the ammonium gets consumed by the plant.
Click to expand...

In some of the published material I linked it stated that the pH swing can be extreme and happen very fast as much a 2 pH point change in a short time as the UREA is converted. If the root zone pH is near a safe point of say 6.0 pH could move to 4.0 or 8.0. But if the pH is already on a border line it could move toxic in either direction, although I think the rapid move is downward. The lower pH area is where ammonia toxicity is of most concern.

just my twopence:sob:
Click to expand...

Good info thank you.
How do you relate this with using UREA as the sole nitrogen source in fertilizer for a hobbyist orchid grower?
 
A question: can we order our experiences by supplying the following information:
1. Fertilizer(s) used
2. Potting medium
3. Medium pH (if measured)
4. Response by plants

As the potting medium is critical to the issue knowing what it is could help. It is also worth remembering that adding lots of N to the medium will have knock-on effects on the availability of other nutrients:
gallery_9296_15892_49618.jpg


This is not the type of discussion with a simply answer.
 
Actually, when I saw the 4 plants originally posted "without Urea/With urea" I thought the first (top left) one was getting too much light and the last (bottom right) one was not getting enough light. :eek:
 
NYEric said:
Actually, when I saw the 4 plants originally posted "without Urea/With urea" I thought the first (top left) one was getting too much light and the last (bottom right) one was not getting enough light. :eek:
Click to expand...

Me too. I also thought the one not getting urea was much better looking. The one getting the urea did not look healthy at all.

I'd love to see if anyone has bloomed a plant with the leaf color that looks like the one that got the urea.
 
I don't want to change the subject, but are there special formulations to get good root growth? Because that is the only thing that was better on previous fertilizers and since my plants have many new growths now, I could focus on the roots the next months.
 
polyantha said:
I don't want to change the subject, but are there special formulations to get good root growth? Because that is the only thing that was better on previous fertilizers and since my plants have many new growths now, I could focus on the roots the next months.
Click to expand...

Is there something wrong with the roots now?
How have they changed?
How do they need to be improved?
 
polyantha said:
I don't want to change the subject, but are there special formulations to get good root growth? Because that is the only thing that was better on previous fertilizers and since my plants have many new growths now, I could focus on the roots the next months.
Click to expand...

There is no question that better roots are made with nitrate and root growth is depressed with ammonium but top growth is increased (this is according to experiments with various grasses) So unless it can be proved by trials that a certain plant grows better in every way using one or the other, use a 50/50 mix to get more balanced (and often increased) top and root growth. Here, growth of Phalies was enhanced with nitrate ratios up to 75% to 25% ammonium. afterwhich growth started to be reduced. All nitrate is no good as is all ammonium/urea. When I say no good, I mean ''not as good'' as it could be.
http://hortsci.ashspublications.org/content/43/2/350.full
 
Ok. Back to the point of paphs in-situ having dark green leaves...

Not all roths grow in such exposed situations as in the photo posted earlier. A more typical leaf colouration of roth in-situ:
http://m0.i.pbase.com/o2/48/839548/1/142283210.uJDqYx7w.Paphiopedi_hEnroe.jpg

Hennisianum in-situ
http://farm3.static.flickr.com/2813/12063441145_fcb0e91939.jpg
http://farm8.staticflickr.com/7310/12064340736_38db65ef9e.jpg

Henryanum in-situ
https://www.orchidsforum.com/attach...canh_9152012_201291573035851675949-jpg.23081/

Several other barbata species in-situ which I have posted in an earlier thread:
http://www.slippertalk.com/forum/showthread.php?t=28510&highlight=hookerae
 
 
paphioboy said:
So this brings us back to the question: Is darker green better than lighter green?
Click to expand...

Thanks for posting these wonderful pics PB! The roth at the top is the same colour as mine. Yey.

I think the answer to your question is probably yes. At least for the barbarta types. Looks like Paphs can grow in very bright light but they always seem to have a yellowish tinge which is to be expected. But the shaded ones look more vigorous and prolific.

After another look at the hennisianums they don't seem to be growing in very gloomy conditions but I think I would struggle to achieve that colour whatever I did even putting them in deep shade, so something is still missing in our culture!
So can someone tell me what that something is?
 

Similar threads

T
Electrical conductivity (EC) and fertilizer concentration
Replies
0
Views
200
terryros
T
gdupont
New Paph. tigrinum, bad roots
Replies
3
Views
743
big923cattleya
big923cattleya
L
New Member
Replies
8
Views
414
NYEric
N
N
Yellowing Phrag. Leaves
2
Replies
20
Views
3K
Heather
Heather
Nelson Wong
Paph Carolines Hands (moquetteanum x rothschildianum)
Replies
4
Views
950
big923cattleya
big923cattleya

Latest posts

Back
Top