This is fine for apartment dwellers or people who live in areas with long winters.   But I should warn you that these buckets only hold up to direct sunlight for about 3 years before they get brittle and split---personal experience in Phoenix, AZ.  You might prolong this by rotating the box 180 degrees every year when you clean up and prepare for a new planting.  Or put a sun blocking screen of some sort in between the window and the plastic of the new planters.  Maybe black to encourage warming.  Cardboard would do.