M519 MS Murashige & Skoog Basal Medium with Vitamins

M519 MS Murashige & Skoog Basal Medium with Vitamins
Wanted to know if someone used it for orchids seeds.
If possible to share the quantity to use.

There are several papers reporting usage of MS medium for germination of orchid seeds. MS in its typical dosage is very strong, so it is often reduced to 1/2 strength, for example.

Anyway, it’s difficult to give general recommendations for the whole family of Orchidaceae. MS may “works” in several cases, but with a poor germination / survival rate only. Sometimes it also will not work at all. So this question can be answered with yes and no: It definitely would be useful to limit this question to certain species.

This paper used MS for germination and shows effects of different MS and sucrose concentrations in later stages for Cattleya cernua. In the MS formula only the macro component has been adjusted, not the micros and organics, and a quite high concentration of activacted charcoal has been used:

Sasamori, M. H., Endres, D., & Droste, A. (2020). Optimal conditions for in vitro culture of Cattleya cernua, a small orchid native of Atlantic Forest and Cerrado. Rodriguésia, 72.

It’s only one example, so it will probably not be that guideline you’re looking for. You should ask for protocols in a more precise way as already mentioned by Orexis.