i've moved to a city, but it's one of those green cities with tons of green space. if you can, try to find a nearby park or woodland trail for mini nature walks and meditation sessions. it might also look weird but hugging a tree can give you a strong earth energy boost. you might also consider downloading an app or buying a cd of nature sounds for your meditation so you can visualize being in nature.
that said, nature is all around us. we are a part of nature. yes, nature is forests and mountains and lakes, but it is also houseplants, pets, germs, air, water from the tap. even the concrete jungle you live in has the elements within it [you could argue concrete is just a processed part of the earth element] it's difficult but you can get creative.
if you want, you might enjoy Deborah Blakes work, she writes about combining the magickal and mundane to find unique ways to see the spiritual in your every day. The Goddess is in the Details is my favourite.