We added a few inches of gravel at the bottom of the pot for drainage.
Next we cut the brown tarp to line the inside of the tower to hold the soil. We used plastic tie strips to hold the tarp in place.
Because potting soil alone dries out so fast we wanted a heartier mixture for our soil. We mixed the potting soil, black dirt and manure on a sheet of plywood and then filled the tower to the top. Pack the soil lightly to prevent too much settling after you start watering the tower.
Now it is time to start planting! We found the best method for doing this is to cut a horizontal slice in the tarp and then a vertical slice up from the horizontal cut to form an upside down T. Before you put your petunias in there make sure you stick the knife or scissors used to cut the slits in the tarp into the drain tile by each petunia you plant so there is a small hole for water to seep out and keep your plants hydrated.
Space the petunias randomly a few inches apart. When you finish the project it will look like the photo above. Don’t worry about how ugly it is now. The petunias will grow fast and fill in the gaps that you leave when you make your tower.
We found that if you fill the drain tile in the middle of your tower every 3-4 days, your plants will do just fine. This is a fun project and it looks even better than the photos.