Jumped the gun: what to do with spawn between now and spring

I'm in the middle of reading Mycelium Running, and in the middle of sheet-mulching my suburban plot, and rather impulsively ordered some King Stropharia and Pearl Oyster sawdust spawn from Fungi Perfecti without really thinking through whether inoculating mulch in the middle of winter was really the best idea. What's the best way to start building some mycelium and getting it ready for its outdoor future?

I could make room for a box or two in the garage, greenhouse, basement, or living space, but if there's an easy way to keep spores contained I'd rather not have too many floating around inside.

I have a variety of possible substrates available, including cardboard, shredded paper, wood chips, sawdust, cotton fabric scraps, and coffee grounds.

My eventually-in-a-few-years vision is a nice thick layer of myceliated wood chip mulch covering the property (0.1 acre in the middle of a subdivision).  I'm hoping some mushrooms will be a nice bonus, but my primary aim is jumpstarting the badly damaged soil ecosystem.

Thanks in advance for sharing any thoughts you might have.

Wood chips mixed with whole grain (wheat or barley soaked enough for it to swell) is the best medium for keeping spawn alive and growing.

Get some small garbage bags (13 gal. or smaller if possible just for easy handling) and fill them about 1/2 full of your blended, very damp, woodchips and soaked grain then add the spawn and tightly close the bag/bags with double twist ties to keep foreign spores from getting in. (fungi spores are in most of the air all the time)

Keep watch and if you see water droplets on the bag's interior you might want to open it and insert one dry paper towel from a freshly opened roll then close the bag back up tight.

The spawn will grow to populate the entire bag as long as the temp is around 60 f or warmer. when the last frost is past, you can then spread your spawn where you want the flushes of mushrooms to be.

Redhawk

Don't worry about floating spores from your own spawn and mycelium - only fruiting bodies produce spores.

I would worry more about contamination with mold spores.

I would go with the grain spawn tek to multiply the mycelium and then go to straw.

Use a still air box to transfer the mycelium without getting mold spored in your new substrate.

https://youtu.be/Xkl7e966qMg is a good start.
For 10$ you can get a whole education from http://www.mushroomvideos.com/ - old but still valid to get all the concepts for sterile work.

I don't get any money form them.