in addition to that also zz plants and sansevieria - for vertical accents and very easy care (or non-care depending on how you look at it ;)). golden pothos (regular, not super variegated variety) as a vine/trailer. also syngonium and swedish ivy (plectrantus) in hanging baskets are good. peperomias, tradescantia , but they need to be kept moist. for larger plants: dieffenbachia (dump cane) and various dracaenas. even some flowers are possible: peace lily and african violets. really, lots of choices.

I've used shiny aluminum foil insulation laid on the ground on the south side of my sunroom to add heat and light. Also have a reflective material, Extenday, on the floor of my greenhouse. You also might consider a better covering on the greenhouse. Mine, double poly, probably blocks at least 50% of incoming light. Just remember more light in means more heat. So you need a good cooling system. If you are talking reflective plywood on the east and west side it can't be very tall or it will block light early and late in the day. And if your covering material is the real issue, trying to push more in won't help much.

Your garden sounds almost identical to mine. We built a raised bed on the side of the garage - ours is to the east. It gets maybe four hours of sunlight a day (plenty of daylight though). I have been successful with tomatoes, green beans, peppers (green, red, jalapeño) herbs, snap peas, lettuce, carrots, cukes, zucchini and plenty of annuals to attract the beneficial insects. I tried onions and potatoes my first year with no luck...but wasn't a "well-versed" veggie gardener at the time. Hope this helps! Kristy :)

Solar tubes and sun tunnels are the same thing, just different brand names. We actually have a sun tunnel although I called it a solar tube in my post. Sun tunnels and solar tubes let in diffused light and the amount of light depends upon the size of the solar tube. We have a sun tunnel in a very small interior bathroom and one sun tunnel lets in enough light so that you can use the bathroom during the day without turning the light on. You should go and see for yourself the amount and type of light that you get from a sun tunnel/tube. If you want sunny light, you should go with a traditional sky light. If you want general background light during the day so that you can use an area during the day without turning on a light, then a sun tunnel/tube works well. As for the windows on the south that look out to a covered deck, I recommend that you find a house with the arrangement and see for yourself--go to open houses in your area. It's hard to tell from your floor plan how big/tall the windows are in your great room, and that will make a difference. However, the light that comes in from windows facing south is much different than the light that you are used to from your current west facing windows and then having those windows look at at a covered deck makes a difference too--you really need to see it for yourself to see if it works for you. The color of your covered deck will make a difference too--if the decking, railings,etcs. are white, it will reflect light and you'll get more light into your great room through the deck. If it's dark brown, it will absorb light and less light will make in into the great room. Also, the height of the roof over the deck will make a big difference too. I have seen covered decks/porches with skylights like another poster suggested, and they work great. It looks like your breakfast nook has lots of windows and they will bring in a lot of light to your kitchen. Good luck!