Feed Me!

[bil]

I'm a great fan of Ray's Klite. I am getting good results. Where I feed the orchids like Stans, that need a heaviier dose I use 20.20.20. That I can get here at 3 euros a kilo inc postage. If I told you what it cost me to get Klite sent over to europe, You would soil yourself. I pay as much in import dues as I do for the fertiliser, and more than that for postage.

Worth it tho.....

[charlesf6]

Originally Posted by estación seca

I just posted a link to a new video on Vanda growing by a Florida Vanda nursery owner, Martin Motes. He discusses fertilizing, and how to tell whether the plants are getting enough, but he doesn't give amounts to add to the water. I wrote to him for clarification.

Watched a bit of this, Guy is a good talker and very interesting.

[Orchid Whisperer]

Originally Posted by u bada

love the fert talks...

While we're at it...

Was just reading an article on AOS mag back issue about ferts... (coincidently) about urea vs non urea based ferts... (and let me note the article was really about nitrogen if that says anything)...

So things to consider from article:

-urea based nitrogen needs to be broken down by micro organisms in media and roots to ammoniacal nitrogen for nitrogen to be taken up, so if it's an established plant in media like bark/moss/etc, then you're fine, if it's fresh media or mounted, won't help too much

-nitrate based ferts, called non-urea based ferts, have nitrogen then can be taken up immediately, so overall these are better (my thought)

-your water quality makes a difference. If you have low tds, or use r/o water, rain water then using urea based i.e. ammoniacal nitrogen ferts will be too acidic of a reaction to media/roots so you want nitrate based nitrogen (look for urea free fert). If you have hard water, then urea based ferts are ok, and actually aid in lowering ph of water so other mineral uptake is helped.

My own professional work focuses on use of native CA plants and mediterranean plants (that's a broad spectrum of plants but...), and these plants have adapted to low nutrient and low water soils through relationships to micro-organisms, like mycorrhizae... so reading this article highlighted the importance of their presence with orchid growing. It is possible with the variability of growth success with grandmother's that don't use fert and those those that use 8 different kinds and amounting to the same success may have more to do with the presence of mycorrhizae... that being, if a microorganism network isn't as developed then fertilizers would be more needed, if quite developed, then fertilizers would be less needed. This of course relates then to media and how to develop this system, and on and on... I can surmise a lot more from this, but suffice to say a happy full established plant must already have a good system growing with it on it's roots and media, and keeping it fertilized could only help it... but on other hand this supports that a poorly growing plant may already be struggling with issues of poor microorganism development in roots, which explains why in many cases you don't fertilize a sick or struggling plant...

Ok, so me personally I've gotten some MSU fert, both for pure water and for well water (from Ray!), for my plants and as mentioned put a little bit every time i water during the growing season and less so when a plant is resting or whatnot... Before I used fish water from water changes with the various aquariums we have, as well as kelp stuff, and fish emulsion, and it seemed to be enough... I honestly can't tell the biggest difference, but certainly I have more healthy plants, it could also be because I'm more on top of watering than I have been this year (last few yours I was working a helluva lot)

Back to fert types, it's worth investigating the various types available, and knowing your water quality. Miracle go I believe, like many, is a urea based fert.

Ubada - The AOS information about urea is out-of-date. Scientific peer reviewed research shows that urea can be absorbed by orchid roots and metabolized internally by orchids. I have posted before about this research; the leàd scientist is Martin Trepanier and the research was conducted on Phalaenopsis. If interested, I can send you a link to the article (PM me). Recently there has been additional supporting research.

Like many other plants, orchids have an enzyme called urease specifically for urea metabolization. This makes evolutionary sense, as wild orchids live in nutrient poor environments, exposure to nutrient is fleeting and there is an advantage to being able to quickly take up nitrogen in a variety of forms, rather than only taking in nitrogen that has been converted to nitrate or ammonia first.

---------- Post added at 05:58 AM ---------- Previous post was at 05:53 AM ----------

Originally Posted by Ray

...and then there are the grandmothers who "never feed" their plants, and the suckers bloom and bloom and bloom...

A friend in my OS does this, or comes close. When asked, he says he never fertilizes his Cattleyas. When pressed, he admits to fertilizing once or twice a year.

[Ray]

Upon doing a bit more research, as well, I agree that urea can be directly absorbed and used by orchids, but what folks fail to realize is that there are different uptake efficiencies depending upon the form and nitrogen and how it is applied.

Nitrate and ammonium sources are preferentially absorbed by orchid roots, while urea is not. By contrast, urea is preferentially absorbed in foliar feeding, while nitrates and ammoniums aren't. That is not to say that there is no absorption of the "not" forms, just that it's not the most efficient.

I think that - depending upon the orchid being fed - the efficiency of foliar uptake by orchids can vary all over the map. Phalaenopsis, with those thick, waxy cuticle layers on the leaves, an adaptation intended to slow transpirational water loss, are very poor at foliar uptake, while thinner-leaved species are likely better.

The gentleman that is the VP of Sales for Inocucor is a paph species specialist, and he has told me more than once that adding a small amount of urea to his feeding regimen has been a benefit. I imagine that his use of his product helps break it down, too.

As an experiment, I made up a "reviver" concoction that contained KelpMax, urea, Epsom Salts, and Inocucor Garden Solution. I had a very old, overgrown pot of a (cochleanthes x bollea) cross that had been totally ignored for years, and was languishing. Within two months of being sprayed daily for a week, it responded with dozens of new growths...

[Ray]

Hmmm... I firmly believe that knowing the "why" behind the "what" gives anyone a solid basis for choosing something simple, and avoids the continuation of the fictitious mythology that has existed so long in the orchid world.

[Orchid Whisperer]

Originally Posted by jkofferdahl

Thanks, Bil, Ray also nailed a nice explanation as well. Again, as an amateur, kitchen-window grower I just use the "fertilize weekly, weakly" adage, despite knowing that the more accurately fertilizer is applied then the better your blooms. The calculator you both mentioned should be an excellent tool to better my own fertilizer application. Thank you.

I quite agree with your 2 most recent posts. And I hope I haven't contributed too much to the OP giving up on raising orchids in favor of growing succotash.

[Orchid Whisperer]

Originally Posted by Ray

"Nitrate and ammonium sources are preferentially absorbed by orchid roots, while urea is not"...

Incorrect.

Here is the research citation, and key findings, included in the abstract:

Phalaenopsis can absorb urea directly through their roots

Trépanier, M., Lamy, M. & Dansereau, B. Plant Soil (2009) 319: 95. doi:10.1007/s11104-008-9852-5

From the abstract:

"The goal of this experiment is to show if aseptic (in vitro) Phalaenopsis plants can absorb urea with their roots." ...

"The 15N analysis of the younger leaves of each plant shows that urea and ammonium are the two preferred forms of nitrogen absorbed, with respectively 47% and 41% of the total amount, while nitrate is only absorbed to a level of 12%." ...

"The medium analysis revealed that no urea hydrolysis occurred before root absorption. Phalaenopsis roots, probably because of the special nature of velamen, can absorb large amounts of nitrogen directly in urea form."

[Ray]

Actually, the Trepanier study doesn't really refute the work of others that say otherwise. It's nice to know the apocalypse is not near, once again, but I think you read too much into it.

The primary issue with that study is the use of immature, in-vitro seedlings. That is an environment that is nothing like those seen by plants in nature, or more mature, cultivated plants. Consequently, the plants have not fully developed the physical - and physiological - tissue structures they will upon maturation ex-vitro, which can affect absorption.

The second issue I have is that the conclusion is based upon continued, constant exposure to the solution. A plant immersed in pretty much any solution for an extended period of time WILL absorb whatever is in it. There is nothing in that study that says that the absorption ratios would be the same in the type of exposure that the plants see when the solution is rapidly poured over them, which is the case in nature and in in-pot or mounted cultivation. In those cases, the solvent water has a strong flushing action, making the exposure to the nutrients short and transient. In that situation, the plant literally has to catch and hold the nutrients before absorbing them, and THAT'S the basis of the studies I was referring to that stated the preferences.

[Ray]

Excuse me?

OW and I have participated in this forum for a very long time, and admittedly have discussed this subject before, but I can assure you that this is anything but an attempt to show off. This forum is one of many that folks participate in to actually learn stuff.

I have not heard a complaint from the original poster, but I must ask what you think you are accomplishing by being insulting?

[Orchid Whisperer]

jkofferdahl is correct in saying this should be in another thread.

Ray, I would be happy to look at the "work of others that say otherwise" that you have mentioned, if you would send the publication citations me in a PM, or far better, start a new thread and post the citations there. (BTW, it is hard to read too much (or too little) into a direct quote.)