In re gardening: all the things you note are possible, but it's also possible he's just having "this means she's up and around and Doing Things" and it's become the symbol, because that's when he sees them. (Whereas if the wife works, she's just not at home, and if she's inside the house she may have Just Woken Up or whatever - gardening represents "awake, alert, doing things". Which is not a good assumption, but hell, lots of people have not-good assumptions.)