Hi, Gayenne. I have asthma, too, and am able to work in the garden — but have to be careful of dusty materials, in particular (as anyone even without asthma really should be, and use a proper mask when working around them). With your doctor’s advice, you can probably figure out how to do things safely.

Good soil in humus-rich — humus being the decayed formerly living material such as rotted leaves and so on, that end up in the soil thanks to microorganisms breaking it all down. We get it to add to our soil by composting (or buying bulk compost and spreading that on the beds). And there are fungi (including molds) everywhere outdoors — the decomposing business that they perform makes the world go round. They’re probably not the same species as the ones in, say, a damp house or cellar, however — so again, your doctor can probably help you with more information so you can make a sensible plan.

I agree with you that you want to manage a successful heap and use its contents, but ask your doctor for some advice if you are concerned about what part of it all you can do yourself, and whether you should use a particular kind of mask, etc., or get someone else to do the turning.