Down the rabbit hole for fertilizers

[Mugsie]

I fertilize my orchids with a variety of fertilizers, Better-Gro, Miracle Grow, and probably a few others I can't remember.

My collection spans a variety of orchids, cats, epi, cata's, dents, phals, BLC's and on and on and on. Reading about the various fertilizers and wanting to make my plants as happy as possible, I've joined the search for the Holy Grail of Fertilizers.

Palmer orchids has a Special blend, with seaweed, calcium, magnesium etc, but it only comes in 8 pound containers. I don't know if this is worth it. There's also MSU fertilizer as well, just to name a couple of the better known fertilizers.

So here's the question - what do all of you use? Why do you use it? What are the results?

Thanks all....

[Roberta]

First, I use very little fertilizer, and my plants grow rather well. I use MSU because I'm using RO water and it adds calcium and magnesium. And the formulation gives a good pH in solution with RO water. (With tap water, the phosphorus even in 20-20-20 isn't enough to adjust the pH because it's so high in calcium bicarbonate, have to add vinegar) So MSU is sufficient (has trace elements, a formulation that overall works). No need to go beyond that. For orchids that need more than my very dilute (every 2 weeks or so) fertilizing, I add a top dressing of tim-release fert (like Nutricote or Dynamite) for an extra shot - nitrogen is the biggie. This is mostly the Catasetinae and Cymbidiums, that grow fast, rapidly. For the rest, they grow slowly and therefoe don't need much.

If you're using tap water, a different formulation might be in order. Primarily, you want to give your orchids a bit of nitrogen for growth, and be sure that you're covered with regard to calcium and magnesium if your water doesn't have those elements in sufficient quantity. (With my "liquid rocks" that would not be a problem)


In short, don't over-think it. Of all the cultural factors, fertilizer is the LEAST important. Concentrate on getting light, air, temperature, watering, etc. right frst.

[Louis_W]

I use Rays k-lite fertilizer and kelpmax. A very eyeballed 1/4 tablespoon per gallon every time (1-2 per week) and kelpmax about once a month or so. (When i feel like it /remember). I definitly dont over think it.

[Ray]

Fertilizer is important, but the demand is extremely low and the formula almost doesn’t matter.

For any plant to add one pound of mass, it must consume and process only 5 grams - roughly a teaspoon - of NPK and 200 pounds of water. The plants you listed probably take at least 3 or 4 years to gain a pound of tissue.

Nitrogen is the important element to focus on, and roughly 100 ppm N applied weekly appears to be the sweet spot. With any fertilizer, divide 8 by the %N in the formula; the result is teaspoons per gallon for weekly doses at that rate, with room for rounding.

For example, a 30-10-10 would be 8/30=0.2666, so a quarter teaspoon per gallon is fine. The K-Lite Louis mentioned is a 12-1-1. 8/12=0.62, so 1/2 tsp/gal is good for that formula.

If you use pure water, you need to add Ca and Mg, as Roberta mentioned., beyond that, changing formulas has absolutely no benefit to the plants.

Kelp products may-, or may not be fertilizers. Most are, but the Kelpak Louis mentioned is a biostimulant that enhances nutrient uptake and significantly improves roots, growth, and flowering.

[Dimples]

I use Dyna Gro Foliage Pro (9-3-6) on all my houseplants. It’s complete so I don’t have to worry about additional supplements. My orchids (mostly phals.) grow and bloom extremely well, but I think that’s more to do with the overall conditions and culture.

[FranningtonBear]

Growth Technology Ltd GTOFB1 Orchid Focus Bloom,1 Litre : Amazon.co.uk: GardenExcuse my stupidity and for jumping on this thread, please could someone answer me these two questions?

Is the dilution on the label correct?

Why shouldn't I use it on my non-Phal's during growth periods as well as during blooming?

thanks in advance, wise-ones

[Mountaineer370]

I'm a long-time user of MSU fertilizer, the formula that says it's for RO/Rain/Tap water. There's a different formula for well water. I'm very happy with the results I get, so I see no need to try anything different. It's on the more expensive side compared to some others, so that may be a factor for some, but with my small collection, an 8-oz jar lasts me a couple years, using it at 1/2 teaspoon per gallon, and fertilizing approximately twice a month.

I agree with what has already been expressed here, that fertilizer is probably the least important of the cultural aspects we can follow, and that there is really no need to over-think it.

[Ray]

Originally Posted by FranningtonBear

Growth Technology Ltd GTOFB1 Orchid Focus Bloom,1 Litre : Amazon.co.uk: GardenExcuse my stupidity and for jumping on this thread, please could someone answer me these two questions?

Is the dilution on the label correct?

Why shouldn't I use it on my non-Phal's during growth periods as well as during blooming?

it is a 1.1% N formula (i.e., you’re mostly paying a lot of money for water). For weekly applications, I would use 9.2/1.1 = 8.36 ml/L - 8 is fine.

They recommend 5 ml/2 L every other watering, but don’t specify a frequency of watering. They also specify 20 ml/wL for cymbidiums, but that’s actually OK for most plants if used weekly.

Blooming or not, plants need food.

Originally Posted by Mountaineer370

I'm a long-time user of MSU fertilizer, the formula that says it's for RO/Rain/Tap water. There's a different formula for well water. I'm very happy with the results I get, so I see no need to try anything different.

Two things:

There is no MSU fertilizer for “RO/Rain/Tap” water. Yes, there are two formulas, one labeled “Orchid Special - RO” and another labeled “Orchid Special - Well Water”.

The first is intended to be used with any pure water supply, that is, one containing no-, to low dissolved solids. Some tap water qualifies, but most don’t. RepotMe buys the stuff and repackages it under that misleading label.

The RO formula contains 8% Ca and 2% Mg, while the Well Water formula contains 2% Ca.

[FranningtonBear]

Thank you!

And I clearly need to rethink my fertiliser choice!

[WaterWitchin]

Originally Posted by Louis_W

I use Rays k-lite fertilizer and kelpmax. A very eyeballed 1/4 tablespoon per gallon every time (1-2 per week) and kelpmax about once a month or so. (When i feel like it /remember). I definitly dont over think it.

I follow a similar routine with the K-Lite and Kelpmax/pak. Use RO water with a 40 gallon reservoir, water plants about once a week. Emphasis on "when I remember" because occasionally straight tap water because I forgot to turn on the RO. Occasionally a mix of about half RO and half tap water. Occasionally straight RO because I'm in a hurry. No overthinking.