I kind of feel like this should be a story of how NOT to grow mushrooms from a kit - I neglected it a lot, and it still turned out OK. So don't be afraid to try it, it's really pretty foolproof!
First off, it took me more than a week just to get the kit out of the box it was shipped in (it's been rather busy around here, to say the least), and so the mycelium (mushroom "roots" - white yogurt-y looking growth) had already colonized most of the straw. I prepped the bag according to the directions, and then set it on a shelf while I focused on getting the house ready for Easter houseguests.
I ignored it completely all weekend, and when I remembered it on Tuesday (today) I found fully-developed mushrooms, ready to harvest! It's a good thing I remembered today, because mushrooms only last a day or two before they're spoiled.
Now to decide which recipe to make with them for lunch today - I'm thinking Broiled Bacon, Mushrooms, and Spinach from The Nourished Kitchen cookbook. Mmmmm . . . is it lunchtime yet?