K-lite?

[karrolhk]

Hi, I read from Ray's site about K-lite fertilizer (K-Lite Orchid and Epiphyte Fertilizer › First Rays LLC) which is said to be based on studies that show the problem with too much potassium.

Could somebody please point me to these studies? Where can I read these studies?

Also, by using a low potassium fertilizer, will that lead to difficulty in blooming which depends on potassium?

[Ray]

The scientific basis for K-Lite was various chapters in Marschner’s Mineral Nutrition in Higher Plants, Benzing’s Vascular Epiphytes, plus a bunch of anecdotal evidence in both related and unrelated areas of study, including microbiology of freshwater mollusks and ceramics. In my mind, one of the best indicators of its likely success is that it mimics what epiphytes get in nature more than any other fertilizer formula.

As is true for ALL fertilizer formulas, we tried it and it worked.

Concerning plants requiring potassium for blooming, people assume more is better, which it is absolutely not. Each plant has its own requirements, and for both P & K, they are quite low. My plants have been fed with K-Lite exclusively for about 10 years, and they all bloom just fine.

A plant is about 90% water. Of the dry mass, about 90% is made up of C, O, H and N. About 9% (so less than 1% of the living plant) is P, K, Mg, Ca, and S, with that last percent being everything else.

[Shadeflower]

I don't know if those studies exist but people have been posting their results for a while already.

here is a post that summarses some impressions

K-Lite has been around a few years now... updates? - Orchid Board - Most Complete Orchid Forum on the web !

you might notice people don't seem to be too happy but I don't think there is anything wrong with K-lite.

As an example, diesel is good fuel and diesel engines will run great on the stuff, if you switch to petrol then your car will seize up. So in the same way you should not pour petrol in a diesle car you should not be using a fertilizer that has not been designed for that plant.

[My Green Pets]

I use it at around 25 ppm N per watering when plants are in active growth.
My plants speak for themselves.
I could experiment with different amounts, or different fertilizers to try to get bigger, faster-growing plants with more, bigger blooms. But I'm fine with how my orchids are growing now.

[Orchid Whisperer]

Originally Posted by Ray

<snip>

A plant is about 90% water. Of the dry mass, about 90% is made up of C, O, H and N. About 9% (so less than 1% of the living plant) is P, K, Mg, Ca, and S, with that last percent being everything else.

Or for an alternate view on orchid dry matter chemistry, see: (PDF) Correlation studies on nutrient content of epiphytic orchids and associated substratum The orchid dry matter contains more potassium than nitrogen for the species studied. The article includes comments on the potassium requirements of orchids, especially during flowering.

[Ray]

Thanks to both Orchid Whisperer and K-Sci for the added discussion.

There are a couple of things we must keep in mind:

First and foremost, tissue analysis only tells us what the plant has been exposed to, NOT what it needs. (I figure that analysis of wild-collected tissue is as close as we’ll ever come to knowing in gross approximation what the need is, considering the niche-plant nature of orchids.)

Keith’s point about uptake dynamics is right on, too. For the most part, typical osmotic dynamics takes place - place a lot of a nutrient in the rhizosphere and the plant will take it up to a greater degree, but that can vary with nutrient ion size and charge, as well. Potassium, specifically, is sought out and “pumped” into plant, even if the external concentration is low. To the best of my limited knowledge, nobody has explain why that it, as the excess is socked away in cell vacuoles and apparently remains unused.

Again, I’ll return to the “niche” nature of orchids and think that the success of a plant with such relatively low K levels, even though the plant actively tries to get more, suggests it isn’t missing anything.

K-Lite has the same basic formulation as one of the well-research MSU fertilizers.

The example you showed from Amazon IS K-Lite, not one of the MSU formulas, even though it is incorrectly labeled as such.

The formulas are as follows:

MSU WW. 19-4-23
MSU RO. 13-3-15
K-Lite. 12-1-1

K-Lite was derived from the MSU RO formula at my request by the person that formulated the MSU formulas, but he is no longer at MSU and wasn’t at the time he did so.

[Orchid Whisperer]

FWIW, the article I linked to explains that N and P are bound in plant organic matter (such as organic matter substratum accumulated on tree "crotches" in a forest), requiring decomposition (mineralization from organic to inorganic form) to become available to plants.

The article authors indicated that K in that substratum is already in inorganic form, and already more soluble. That's a double-edged sword; while the K is more plant-available, it can also be leached away. From the plant tissue analysis, it seems that orchids do accumulate what K they need.

Given the critical nature of K in plant metabolism (protein synthesis, sugar transport, N and C metabolism, and photosynthesis, etc.), plants may accumulate it for when they need it and the supply is scarce (compare to animals accumulating fat for 'lean times').

Whether we provide K in a fertilizer with other macronutrients, or provide it in the form of other supplements (seaweed extract provides it, for example), what matters it that plants obtain what nutrients they need to perform well.

[Ray]

Originally Posted by Orchid Whisperer

…what matters it that plants obtain what nutrients they need to perform well.

Yep.

Again, the trick is to avoid any deficiencies without over-applying anything.

[K-Sci]

Originally Posted by Ray

Yep.

Again, the trick is to avoid any deficiencies without over-applying anything.

Who should not use K-Lite?
-Keith