Any alternative to MSU fertilizer for well water in Europe?

[ChrisMalaga]

Hello! I currently use Orchid Focus to fertilize my orchids. In winter I use water from my dehumidifier, but my collection is growing and water is not being enough. Also, in summer I'm forced to use tap water (I'm not considering osmosis water at the moment for many reasons, and it rains so little here that I can't collect enough rain water).

I bought a PH down solution that ensures the PH is 5,8 (PH of my tap water is 8.7). My water is very hard (270 ppm), most of the salts should be Calcium and a little (maybe too little) Magnesium. The problem is any good orchid fertilizer I see in Europe has calcium, which my tap water contains already a bit too much.

The only orchid fertilizer that seems to suit my water would be the MSU fertilizer for well water (rePotMe sells it), but it's not affordable at all, considering shipping to Europe is more expensive than the fertilizer itself.

Unfortunately RainMix doesn't have a similar fertilizer for well water.

Has anyone found a good fertilizer, similar in composition, with little or no Calcium, available in Europe?

[Mr.Fakename]

I really like those Products - Biobizz

That's a bit different than what you're looking for, but I've had great results!

Epsom salts will raise your magnesium, it's readily available and pretty cheap.

[ChrisMalaga]

Many thanks for your suggestion! However, I found it a bit difficult to find the exact composition of those products... after some research, I found that in Bio Grow most of the Nitrogen is organic (urea?), then some amoniacal (difficult to use by the plant) and only 0,2% is nitric, which is the best nitrogen for orchids. I was looking for something with no urea and where most or all the nitrogen is nitric.

[Roberta]

Actually, ammonia nitrogen is the form MOST easily utilized by the plant, not least. In urea-free formulations, nitrogen is in there as ammonium nitrate. (The chemistry dictates that you have both a cation (positive) like NH3+ and anion (negative) like NO3-, you can't have one kind of ion without the other. Actually, orchids CAN utilize urea, and other organic, nitrogen. In nature, the only nitrogen they get is organic (from rotting plant material, bird poop, etc. that washes down in the rain)... They would get no ammonium nitrate at all, that's a human-made compound.

[ChrisMalaga]

Hello Roberta!
I read some articles that say that urea is used by orchids, however they generally talk about bark setups, where there are some colonies of the bacterias responsible for breaking down ammonia and urea and make it available to the plant (I read that this process is so fast that it can be available in 24-70 hours).
I forgot to mention that I'm using a setup with LECA and self watering for many of my orchids, I use volcanic rock and coal for Cattleyas and Brassavolas, others moisture lovers are grown in self watering + pumice stone. I did notice that the root tips of my orchids were often burning when I was using ammonia/urea nitrogen. I can't be sure 100% this was the cause, but it seems like it's getting better with my new fertilizer. I think the bacterial colonies near the roots of my plants have a really hard time surviving, I even had to soak plants growing in bark in hydrogen peroxide 3% due to some bush snail infestation recently, so I think I killed everything. I'm also a heavy flusher, so that may not help either. I think nitric/nitrate nitrogen is the one that works best for me at the moment, but I'm open to new fertilizers as long as I'm sure I don't burn the green tips of the roots

---------- Post added at 09:45 AM ---------- Previous post was at 09:29 AM ----------

Do you think that bacterial colonies would survive in LECA? Another option would be to get some product containing beneficial bacteria, but would those survive in an inorganic setup? Moreover, my LECA has a tendency to raise PH (I think it's a common problem with LECA).
If adding bacteria to my water is the solution, the problem would be solved for me, because there is a very common fertilizer for orchids that is sold in supermarkets here, ready available, that doesn't contain any Calcium and Magnesium (I can add epsom salts), but has urea (contains birds poop). Would really be great to know I can use this without risks.

[Ray]

Urea can be taken up directly, but the degree to which it happens is is quite limited through the roots.

When urea breaks down, ammonia is the first byproduct, which can be taken up more easily. That ammonia can also be broken down, forming nitrate, also easily absorbed.

Yes, microbes can live in LECA.

[ChrisMalaga]

Thanks Ray.
However, I have recently read this academic article which talks about the ideal proportion between nitrate and ammonium nitrogen, which studies the effect of different ratios on two epiphytic orchids: a Dendrobium and a Phalaenopsis. It seems like the best ratio would be 70-75% nitrate and 25-30% ammonium. Other proportions resulted in a lower absorption of other nutrients and concentration of 75% ammonium resulted in clear toxicity to the plants:
Impact of Nitrate and Ammonium ratio on Nutrition and Growth of two Epiphytic Orchids

Unfortunately I see that many fertilizers show a much higher proportion of urea and ammonium than nitrate, which I think is because it's more expensive.

Another experiment I was thinking of is to use some Magnesium nitrate and add it to a common fertilizer which contains higher content in ammonium and urea, thus raising the amount of nitrate and magnesium, hopefully reaching the perfect ratio. How to do that, I will try to understand...

[Ray]

The nitrate to ammonium split (none have urea) of some excellent orchid fertilizers are:

MSU WW - 70.5% nitrate, 29.5% ammonium
MSU RO - 94.7% nitrate, 5.3% ammonium
K-Lite - 95.3% nitrate, 4.7% Ammonium
Jack's Cal-Mag - 80% nitrate, 20% ammonium
D-G Orchid Pro - 62.8% nitrate, 37.2% ammonium

[estación seca]

Fine details like fertilizer composition are far less important than proper growing conditions: temperatures, humidity, light.

[Ray]

Originally Posted by estación seca

Fine details like fertilizer composition are far less important than proper growing conditions: temperatures, humidity, light.

Agreed 100%.

Unless you are grossly under- or over-feeding your plants, formula doesn't come into play until you've optimized pretty much everything else.