We purchased a tall planter and would like to know if and what we could put in the bottom before we add soil to make it less heavy.
You can fill 1/4-1/3 of the bottom of your planter with an inert filler that still lets the water drain freely. Materials that can be used are packaging peanuts, or even compressed Pet bottles. After you put in your filler cover it with a landscape fabric before you fill in the potting mix.
Please refer to the following website for additional information: The Secrets to Successful Container Gardening