Very low PK fertilizers. (K-lite)

[DavidCampen]

I see that Firstrays is selling a fertilizer that he calls K-lite. It has a radically low amount of phosphorus and potassium compared to the levels of nitrogen, calcium and magnesium 13-1.3-1.3-(10% Ca, 3% Mg).

Ray, I would love to hear about any experiments performed with this formulation. Do you suggest using it all year around?

[keithrs]

I'm involved in the trial but I have to be honest and say I have only used it about 6 times in the last 3 months... It has been raining and my light levels, I felt where to low to fertilize more than that.

There has been some interesting results with some of Ray's plants that he posted on another board....

You will find some very good info on Slippertalk about low k diets.

[billc]

Like Keith said there are some well reasoned arguments for a low K diet on Slippertalk.(Look under Slipper culture) A few folks had made there own concoctions up and have seen some nice results. I'm hoping for the same with Ray's formulation.
I've been using it for about 2 months without a problem.

Bill

[Ray]

David, as others have pointed you to the discussion at Slippertalk, I'll let you read that.

There are currently 33 people in 18 US state, France, Holland, and Israel participating in the trial, plus 3 others not participating in the study, that have told me that they were glad to find a source of the low-K material, as they have long felt the potassium to be a "bad player" in orchid culture.

So far, I have heard no negative reports.

I figure I'll likely be the first to see any, as I grow in inert media for the most part. Bill Argo (developer of MSU fertilizer formulas, and the K-Lite for us, which was derived from the RO version) suggested we keep a look out for:

Potassium deficiency - you will see an edge burn that starts on the lower leaves and works its way up the plant.

Phosphorus deficiency - The growth will stall, and the plants will either take on a dark green cast, or they will have a reddish color in the older leaves.

[DavidCampen]

Thanks to everyone who pointed me to the discussions in the slippertalk forum. Lots of good threads to read there.

[Exo]

Arent those both nutrients that assist in blooming?....this seems like it would be counterproductive to me.

[Ray]

Originally Posted by Exo

Arent those both nutrients that assist in blooming?....this seems like it would be counterproductive to me.

The concept of phosphorus being a "bloom booster" is overhyped marketing.

When Dr. O. Wesley Davidson of Rutgers University invented what is now Miracle-Gro 30-10-10, folks were thrilled by the foliage growth they saw. Unfortunately, that high nitrogen content also tended to reduce, delay, or stop flowering altogether, so they added cheap phosphorus compounds to "dilute" the nitrogen back to an acceptable level, therefore allowing the plants to bloom (not "boosting" it).

In fact, plants have very low phosphorus demand, and they tend to take it up and sock it away in vacuoles, in case there is a deficiency.

In the case of potassium, we are speculating that orchids - epiphytes in general, actually - have a much lower demand than do most terrestrial plants, and may actually have lost some control of its uptake, allowing it to interfere with the uptake and use of other cations.

That speculation is based primarily upon tissue analyses, and analyses of the biomass of the forests where they live in nature (which are surprisingly low in K, compared to soil).

[Exo]

Yeah..I've read studies about nutrient availability in rainforests, Nitrogen is relatively abundant, yet almost all of the other nutrients are sequestered away in the plants themselves, the soil is actually rather barren.

Makes me wonder if perhaps the best fertillization program for orchids would simply be a "compost tea" sorta thing...leaves brewed in rainwater..stuff like that. I use rainwater most of the year, and I have a cattleya that blooms well every year...and I almost never fertillize it. Food for thought, I suppose.

[keithrs]

I'm really debating about going with a guano tea program full time.... You can make a "K-Lite" program that I think will work well. The problem would be with people that have large collections.... You would need large amounts of tea.

[DavidCampen]

Originally Posted by Ray

The concept of phosphorus being a "bloom booster" is overhyped marketing.

When Dr. O. Wesley Davidson of Rutgers University invented what is now Miracle-Gro 30-10-10, folks were thrilled by the foliage growth they saw. Unfortunately, that high nitrogen content also tended to reduce, delay, or stop flowering altogether, so they added cheap phosphorus compounds to "dilute" the nitrogen back to an acceptable level, therefore allowing the plants to bloom (not "boosting" it).

If Miracle Grow 30-10-10 having an N:P:K ratio of 3:1:1 is high nitrogen then shouldn't K-lite with an N:P:K ratio of 100:1:1 be called super high nitrogen?