Here, I'll show a solution to light-weighted your planter. But, firstly we need...
Step 1: Items
1 heavy clay planter
A few dry banana fronds or coconut husks
Step 2: The Filling
I notice over a period of time that when I used the coconut husks, the dirt sink much slower that the banana fronds.
Step 3: The Planting
Lastly, I plant it with a coconut seedling. Now, the planter is much easy to handle because the weight is reduce about a least 50%.
No more back breaker for me.