Potting soil is not cheap, so whether you are using a large planter as a statement piece for a smaller plant or for a large tree, in most cases you do not need to fill the whole planter with soil. Pot fillers are also a great opportunity to recycle non-biodegradable trash like plastic.
So what should you use to fill the bottom of a large planter?
First, research the plant or ask your local garden center what kind of depth the plant or tree’s roots need. That will give you an idea of how much potting soil you will need. We recommend using a high-quality potting soil and not garden soil as soil outside can be contaminated with weeds and other substances that will not help your plant.
Once you know about how much space will be leftover depending on the depth of soil you need, you will be able to choose a filler.
Lightweight Filler for Pots
If your large planter is made of clay or another heavy material, chances are you will want to go with a lighter weight filler. If the planter is being placed in a more permanent spot, this may not be important to you. The lightweight filler is also good for large lightweight planters that you may want to move occasionally.
Options for Lightweight Pot Fillers
- Recycle Plastics
- Plastic Water/Soda Bottles
- Plastic Milk Jugs
- Plastic Grocery Store Bags
- Reuse Packing Materials
- Packing Peanuts (You can put the peanuts in an empty potting soil bag to keep them more secure and better contained if you decided to repot. Also make sure they aren’t the kind that dissolve when wet.)
- Styrofoam Blocks
- Unused Plastic Pots Turned Upside Down
- Recycled Crushed Cans
- Natural Materials
- Wood Chips, Pine Cones, Leaves, Sticks (These materials will break down over time but work fine for seasonal planters.)
- Recycled Cardboard, Newspaper (Also for short term use only.)
Heavy Pot Fillers
There are a few reasons you may want to fill your large planter with a heavier filler. Maybe you have a tall lightweight planter that you want to make sure is more sturdy, especially when using it for a tall tree. Maybe your planter will be in a public place where it could get bumped into or stolen. Heavy materials will also work for more permanent installations. Whatever the reason, these are some options for heavy pot fillers.
Options for Heavy Pot Fillers
- Broken Pieces of Ceramic, Brick, etc.
- Large Rocks
- Wood Logs
Make sure the filler materials are sturdy enough so when you add the soil it will not shift. It is also a good idea to add a piece of landscaping fabric on top of the filler to prevent too much soil from falling through the cracks.
These are just a few ideas, but you can get creative with other fillers, just use whatever you have lying around. Usually, there is no need to go buy a filler, chances are you already have items you can recycle.
Have you used other materials you liked? Let us know in the comments.