This is a great way to utilize all those clay pots we gardeners sometime collect over the years. Having all the plants in one place saves time and water.
Also, don't limit yourself to just clay pots, you can use any relatively round object that has a hole in the bottom. I also made a neat version out of old tea kettles, which you can view on the website link I gave above.
Step 1: Step 1 - Prepare the site
Note: Depending on the height of the pots you have chosen, you may need to lengthen or shorten the piece of rebar. I would suggest you measure the height of all the pots ahead of time and then add 24" to that total before cutting your rebar.
Step 2: Step - 2 Start Stacking
Step 3: Step 3 - Continue Stacking
Step 4: Step 4 - Finish Stacking and Plant
Step 5: Step 5 - Finished
To water, start at the top and water slowly. Pour the water on until it starts to run out. Stop watering that pot and go to the next. Continue until all pots have been watered. Wait several minutes then repeat the process. Clay pots tend to dry out quickly, so you can slow this down by sealing or painting the pots first and lining the inside of the pots with newspaper. You can also use water absorbing crystals in your potting mix. This tower may need to be watered twice a day if you have temps in the 90s or more.