We’ve had frost and feel the outdoor growing season closing. Tovah Martin, author of The Unexpected Houseplant: 220 Extraordinary Choices for Every Spot in Your Home reminds us that we can now concentrate on the indoor growing season. I confess that I have never been much of a houseplant person. In the past I have grown spider plants, asparagus fern and grape ivy in pots hanging by holders I macramé-ed myself, supermarket cyclamen, avocado pit seedlings and occasional…