Hi Kim –
Your post made me smile a bit because there are so many ways to enrich your nature study! I have posted a series about nature study on my blog – and two of those posts are direct answers to your tow questions: nature study on a porch (or balcony) and nature study in winter. Here is a linkto them:
http://mysouldothdelight.wordpress.com/category/nature-study/
Another way to do some indoor nature study would be to have terraniums of plants and aquariums with fish in your home. Add a few bird feeders or a little birdbath outside with a windowsill box of flowers that attract bees and butterflies…you would be well on your way!
Nature study is one of our favorite subjects!