Nutrition is extremely important for germinating spores. Once they germinate and start building hyphae, they need to start taking in nutes in order to continue the process and create a thick mat of myc. On top of that, there are specific triggers for the germination of spores. The major one is the presence of usable nutrition. Some mushrooms, like Psilocybe mutans for instance, are very fond of horse and cow dung and are resistant to germinating on anything else:
"McKnight found that 95% of the spores germinated in horse dung decoction, 94% in cow dung, 73% in pig dung, 28% in dog dung, and 26% in chicken dung deooctions. The decoctions were aqueous extracts of the dried dung. McKnight found that only 0.1 to 4.1% of the spores germinated in distilled water. Negative results were also obtained with 0.1% and 0.01% water solutions of malt extract, yeast extract, casein hydrolysate, and ribonucleic acid. Extracts of orange juice, of grass, and of alfalfa also gave negative results. Water solutions of furfural and hemoglobin resulted in 8.9% and 12.1% germination respectively. Spores treated in a water bath with temperatures ranging from 30°-60° C for periods of from 5 minutes to 5 hours did not germinate better than the water controls. However, 9.1% of the spores germinated when they were heated to 50° C for 15 minutes and then frozen for 24 hours." - Neal K. Van Alfen
Granted, that's only one species and cubensis seems to be a lot less picky when it comes to nutrition. However I suspect that if we want to find a miracle germination recipe, we have to look at the environment in which a species grows. In their natural environment cubes like cow and horse dung, so a manure agar like the one above would probably be our best bet for germinating difficult spores. Likewise, stubborn woodlover spores would probably get a germination boost from an agar made from wood broth.
Now, if you have a culture with some difficult bacteria, perhaps you could clean it up using water agar. In theory, the myc from the transfer could utilize the bit of nutrition from the transfer wedge to grow out a bit on the water agar, and the bacteria should starve.
Edited by HrVanker, 06 January 2021 - 07:22 PM.