Very low PK fertilizers. (K-lite)

[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.

[tucker85]

Originally Posted by 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.

I used Merrill's Compost Tea a couple of years ago and my orchids did not perform well. I think a lot of the nitrogen in compost comes from urea and ammonia and orchids can't readily utilize it. For the past year I've been using fertilizers that get nitrogen from nitrate only and I've seen a big difference in growth rates. A study done by a university in Texas (it might have been Texas A&M) showed that orchids utilize nitrogen derived from nitrate much better than nitrogen derived from urea or ammonia. That study is sited in the 4 part series called 'Growing the Best Phalaenopsis'. You can find it online. In any case I don't feel that compost teas are effective when used alone. Maybe they could be alternated with a chemical fertilizer.

[DavidCampen]

Originally Posted by tucker85

A study done by a university in Texas (it might have been Texas A&M) showed that orchids utilize nitrogen derived from nitrate much better than nitrogen derived from urea or ammonia. That study is sited in the 4 part series called 'Growing the Best Phalaenopsis'. You can find it online.

I will look for that. I find it curious that nitrate would be much superior to ammonia especially since plants convert nitrate to ammonia to be utilized.

[keithrs]

Originally Posted by tucker85

I used Merrill's Compost Tea a couple of years ago and my orchids did not perform well. I think a lot of the nitrogen in compost comes from urea and ammonia and orchids can't readily utilize it. For the past year I've been using fertilizers that get nitrogen from nitrate only and I've seen a big difference in growth rates. A study done by a university in Texas (it might have been Texas A&M) showed that orchids utilize nitrogen derived from nitrate much better than nitrogen derived from urea or ammonia. That study is sited in the 4 part series called 'Growing the Best Phalaenopsis'. You can find it online. In any case I don't feel that compost teas are effective when used alone. Maybe they could be alternated with a chemical fertilizer.

Thanks for the info Tucker! I've decided not to go that route... At least for now!

[DavidCampen]

Actually, I have decided that the NPK of a blended fertilizer is not very usefull and in fact misleading since it ignores calcium and magnesium which are at least as important as nitrogen, phosphorous and potassium.

I think that one can blend a good fertilizer using only calcium ammonium nitrate (YaraLiva Calcinit), magnesium nitrate (Magnisal) and potassium dihydrogen phosphate (MKP).

First determine the ratio of calcium ammonium nitrate to magnesium nitrate that will give you your desired ratio of calcium to magnesium. This also determines the percentage of nitrogen. For example, a 2:1 ratio of calcium ammonium nitrate to magnesium nitrate gives you 4:1 calcium to magnesium ratio and an NPK of 14-0-0 (12.7% Ca, 3.2% Mg). Then add MKP to get the desired amount of phosphorous and potassium. For example, 2:1:0.25
blend of Calcinit, Magnisal and MKP gives:
NPK 13-4-2.7 (11.7% Ca, 3% Mg).

[tucker85]

Originally Posted by DavidCampen

Actually, I have decided that the NPK of a blended fertilizer is not very usefull and in fact misleading since it ignores calcium and magnesium which are at least as important as nitrogen, phosphorous and potassium.

I think that one can blend a good fertilizer using only calcium ammonium nitrate (YaraLiva Calcinit), magnesium nitrate (Magnisal) and potassium dihydrogen phosphate (MKP).

First determine the ratio of calcium ammonium nitrate to magnesium nitrate that will give you your desired ratio of calcium to magnesium. This also determines the percentage of nitrogen. For example, a 2:1 ratio of calcium ammonium nitrate to magnesium nitrate gives you 4:1 calcium to magnesium ratio and an NPK of 14-0-0 (12.7% Ca, 3.2% Mg). Then add MKP to get the desired amount of phosphorous and potassium. For example, 2:1:0.25
blend of Calcinit, Magnisal and MKP gives:
NPK 13-4-2.7 (11.7% Ca, 3% Mg).

You certainly have a much better understanding of the chemical makeup of fertilizer than I do. I agree that calcium and magnesium are important elements according to everything I've read. Unfortunately Magnesium and phosphorus compete with each other for uptake by the plant. I've been using a calcium/magnesium supplement by itself, twice a month on my orchids and they seem to be doing well.

[DavidCampen]

Here is the article:
http://www.hrt.msu.edu/faculty/Runkl...sis_Part_2.pdf
"Results from a recently completed study at Texas A&M University suggest that fertilizers high in ammoniacal nitrogen are not desirablefor the best vegetative growth and flowering."
Who knows what that really means, I would have to see the actually paper to see what parameters they did or did not control.

And speaking of controlling parameters, as I have mentioned, K-lite is also low P. If people are seeing benficial results from K-lite maybe it is from the low P. I wonder if it is the high P levels in many fertilizers that cause problems by reducing the availablity of calcium, magnesium, iron and copper. Maybe a P-lite with low P but higher levels of K would be even better.

Also from the above referenced article:

"A recently completed study showed that phalaenopsis that did not receive adequate levels of potassium may
appear healthy for several months, producing a similar number and size of new leaves as those receiving adequate potassium. As soon as spiking has taken place and while the young inflorescences grow, the limited pool
of potassium in the leaves and roots is remobilized to support the reproductive growth and the lower leaves start to show symptoms of potassium deficiency. Although plants that were deficient of potassium produced flowers, a few lower leaves were lost. All phalaenopsis planted in a bark mix and lacking potassium eventually died."

[keithrs]

Originally Posted by DavidCampen

Here is the article:
http://www.hrt.msu.edu/faculty/Runkl...sis_Part_2.pdf
"Results from a recently completed study at Texas A&M University suggest that fertilizers high in ammoniacal nitrogen are not desirablefor the best vegetative growth and flowering."
Who knows what that really means, I would have to see the actually paper to see what parameters they did or did not control.

And speaking of controlling parameters, as I have mentioned, K-lite is also low P. If people are seeing benficial results from K-lite maybe it is from the low P. I wonder if it is the high P levels in many fertilizers that cause problems by reducing the availablity of calcium, magnesium, iron and copper. Maybe a P-lite with low P but higher levels of K would be even better.

Also from the above referenced article:

"A recently completed study showed that phalaenopsis that did not receive adequate levels of potassium may
appear healthy for several months, producing a similar number and size of new leaves as those receiving adequate potassium. As soon as spiking has taken place and while the young inflorescences grow, the limited pool
of potassium in the leaves and roots is remobilized to support the reproductive growth and the lower leaves start to show symptoms of potassium deficiency. Although plants that were deficient of potassium produced flowers, a few lower leaves were lost. All phalaenopsis planted in a bark mix and lacking potassium eventually died."

Being that chemical engineering is why out of my league.... I will be of no help, BUT....... You should post a thread on Slippertalk and see what the folks on there say.

[DavidCampen]

Originally Posted by keithrs

Being that chemical engineering is why out of my league.... I will be of no help, BUT....... You should post a thread on Slippertalk and see what the folks on there say.

I know nothing about growing slipper orchids so I have stayed out of the conversations there.