How deep does a raised bed on a patio have to be to grow veggies?

Your Gardening Questions covers the gamut of gardening questions from our Plant Talk Radio listeners. Over the phone, or by email, Fred answers them all. Make sure the latest episode is in your favorite podcast player, like Apple Podcasts, Google Podcasts, or find a podcast player at http://www.subscribeonandroid.com.http://www.planttalkradio.com