If moisture didn't get in where you stored it then possibly it had been sitting in the sun previously and the existing moisture in the bag was driven to the top. With no air circulation or possibility of drying out the mould would have made a start. But remember, it will be mould which was already in the bag, only it got a jump start on all the other micro organisms. If you left the affected soil in an open airy place with a bit of moisture the micro organisms will sort themselves out and get it all back into balance. But as the others have said, make sure you don't breath in any spores from the mould. And that's the same story for any bagged potting soil that has dried out as well. In drying, all the moulds produce spores which then drift around like a fine dust when the soil is disturbed. If you breath that in you can get what is often called "Farmers Lung"

Try looking up "Greenhouse supply/suppliers/equipment" in your local phone book for the Promix. I can get the huge bales (use to be black, now I have ones called promix BX that are white) 3.5 cubic ft compressed, for about $25 each. I can NEVER find this stuff in the retail stores, but all the nursury businesses around here get it from greenhouse suppliers. I found one who had a yard in a nearby town and I now pick up about 3-4 bales a year. They don't advertise to the public but seem happy to sell it to me when I walk in the door with cash. One time I wanted to use a credit card and they grumbled about that (they are set up to direct bill the large nursury customers)and they always look puzzled that I don't have a "tax number", but if I go with cash it is quick and easy. Nancy

Irrigation: I don't think the high/low there is enough to worry about on a pressurized system. I think my system is 8 psi, somewhat standard. Of course it might be easier to do a low pressure system, and use your pump just to fill a high reservoir that then flows down to all beds. A mini water tower. Lots of options there. I would watch some videos on high pressure and low pressure "off grid" systems to get a feel for it. Using adjustable emitters everywhere makes it easier. I got 50 adjustable emitters for $4.47 on ebay. Play with a test setup before you commit. Dirt: You are building big planters, so you may want to look at getting a bulk delivery to fill them. In my area there are suppliers for organic potting soil by the yard. I'd call around and look for that. Are you near any commercial greenhouse operations? They might give you a lead, especially if you describe what you are doing.

We've two wood burning fireplaces in our current house. The Family Room gets used about 30-40 times per year, living room about 5. Wood-burning fireplaces were a must for our new house. We really enjoy them. Health. The issues @Springtime raised are real issues. Relative to other risks to our health are quite low though. You are likely to loose massively more years of your life to being overweight, obese, having a sedate lifestyle, or being on or near a U.S. road than to any issues with a wood burning fireplace used EVERY DAY. That said, reducing the risks with good fireplace design and ventilation are still a good idea. For instance, outside vents directly in to the fire box provide only about 200 cfm so we run our MUA @ 400 CFM when burning a fire and for at least a couple of hours after it's gone out. This insures that combustion by-products mostly go up the chimney. I also open the flue and run the MUA when cleaning ash out. Energy. Wood-burning fireplaces are not energy efficient. But, perspective. An hour of fire with an outside ambient temp of +20°f uses the same energy as driving an SUV about 1.2 miles IIRC (need to double check that number though). We ride bicycles for nearly all of our local transportation and our cars are electric (and charged by solar) so all in all the wasted energy of all of our fires for a year is a rounding error compared to how much less energy we use for transportation than an average couple or family. Whether health or energy efficiency, every little bit helps. But we shouldn't spend a lot of time and energy swatting flies when an elephant is getting ready to crush us.