As to the first point, I agree, maybe Holland would a be better option given brexit uncertainty. Holland has a strong horticultural sector and if the language barrier is an issue, the Dutch tend to speak English pretty well.
As to second point, I couldn't recommend any product available in the EU as I haven't tested any with orchids. All I can do is share my own prejudice as to the type of product I would look for.
I have some reservations about the whole effective microbes or EM approach as based on the work of Higa. The results even by his own admission are not reproducible.
https://en.wikipedia.org/wiki/Effective_microorganism
So when you see Lactobacillus, Rhodopseudomonas, and Saccharomyces cerevisiae (aka baker's yeast) listed as the main species included, then you're looking at one of the EM formulations. It's not inconceivable that this stuff might have utility but I wouldn't spend any money on it. I'm more likely to experiment with vermicompost tea instead.
I've become very interested in the work on PGPB's or plant growth promoting bacteria. There is some very good research in this field. It turns out that most of the PGPB's share a number of activities. Approx 70% of them produce auxin (IAA), many release bound or insoluble phosphates, they produce siderophores which promote micronutrient uptake by roots and also suppress opportunitistic bacteria, they inhibit pathogenic fungi by excreting chitinases and glucanases, they relieve stress by modulating feedback in the ethylene pathway and they are able to induce systemic resistance to pathogens in plants. Here is an older review with a list of commercialised PGPB species in section 2.1:
https://www.hindawi.com/journals/scientifica/2012/963401/
You will note that bunch of these are from the Bacillus and Pseudomonas genera.
Ray posted a link to a list of bacteria typically included in Garden Solution and as far as I remember there was a good overlap with known PGPB species. This suggested to me that the guy's who developed Garden Solution had done their homework. The only product that I've found here that demonstrates some knowledge of PGPB research is this one:
https://thenutrientcompany.com/products/tnc-bactorr-s13
The bacteria are all from the genus Bacillus and are species which appear repeatedly in various PGPB lists. The selection is a bit limited, but there is an obvious reason for this. Bacillus species are spore formers, and so they can produce it as a stable powder as the spores will last for years in a viable condition. I might experiment a bit with this product this summer, as some strains of B. licheniformis produce chitinase which should inhibit fungal pathogens, it would be nice to know whether the strain they used has this activity, and I can test for this. Also Bacillus species are quite tough and adaptable and would be more likely than non-spore formers to survive in orchid potting media if they dry out occasionally.
This product is supplemented with humic acid and kelp extract. Both of these have been reported to help with the establishment of and effectiveness of PGPB's in various applications. Garden Solution uses a similar system, but with a much more complex mixture of bacteria. Using seaweed extract and humic acid together after introduction of the PGPB's will help to maintain them in the pot medium as well, remember if you want them to survive you need to feed them as well.
when I open Tapatalk and see this line in the header thread, I just have to look and see whats going on ...
