I doubt it that you can grow plants on the green grass inside the Life House, considering the fact that soil cannot be placed in any indoor homes. But if you are very psyched up to have soil in the indoors of the Life House, you could look up some flying carpet tips. You may be able to put the pot in the ground somehow, to make it look like soil.
And for the BQ, it's up to you.
Life House - Lots of space outdoors, Medium space inside ----- Myth House - Lots of space outdoors, Lots of space indoors ----- Wysteria Villa - Medium space outdoors, medium space indoors ----- If you'd like a cozy little home, choose Wysteria Villa. - If you like to be creative and build a lot, choose the Myth House. - If you love nature, you could pick the Life House.
You need to prepare plots or have pots in any house. Indoors you need pots for the most part. Out doors you can use plots or pots, except Large plants that require plots. You learn the spells from the gardeners in Krok and Mooshu for the various sizes of soil prep spells. Sm and Med regular plot spell you learn from the gardening quest.