An international network of/for intelligent organisms
The spores need to dry for a few weeks and will then hatch into amoebae if you add water. The haploid ameobae feed off bacteria I've grown them up in liquid culture by adding spores to a suspension of E.coli - not really practical unless you work in a lab but I've had success just adding spores to wet oat agar - it gets pretty grim but the bacteria that start growing on the agar will feed the amoebae until they decide to fuse. Young plasmodia aren't easy to spot - they start as millimetre sized patches will little pigmentation, takes around four weeks for them to form.
You could also try a natural approach - shove moss, leaves and twigs into a plastic tub, dampen well and throw spores on top
Thinking about about this last night ( I'm a world class insomniac). The bacteria don't need to be alive and good old coli isn't a great choice if you're not in a lab - it smells awful for one thing.
I wonder if lacto bacteria might be better - If I get round to it, I'll try the following - make up 2% malt extract in water, inoculate with cultured buttermilk and leave it around until it stops fizzing. Heat kill at 70C for five mins, allow to settle, decant, mix sediment in water( to remove lactic acid) , settle and decant again. Add spores to dead bacteria suspension, leave 1 week then spread on oat agar, wait......
Can't we simply use a Yogurt (or so) for it's dead bacteria, and just ad baking soda to neutralize remaining lactic acid from serum (test with ractive paper) ?