"Scatter house plants around some rooms" is a great way to build value. On Million Dollar Listings LA they had a guy who was able to sell his home for an few extra hundred thousand simply because the buyer like the furniture and "houseplants." Seriously, it was awesome! However, telling people to add houseplants is a death sentence for most indoor greenery, perhaps you should share the benefits of Soil-Free plants, like what they've been doing in Europe for 40 years, there is NO DIRT and NO GREEN THUMB REQUIRED! Check out an awesome project on Kickstarter.com, search "Plants" you'll see what it's all about. I guarantee that a few of these plants will make the entire house POP to life!