Horticulturalist here :)
Consider whether you want to move the planters and whether you will need to divide the plants and repot - a heavy large planter full of soil would make this difficult (e.g. bamboo will fill/outgrow the pot and need dividing from time to time).
Also consider the best growing medium / potting mix. Some plants need more drainage than others for example. Tropicals generally tend to prefer a loose, acidic, well-drained, fertile soil high in organic matter. Common tropical plants, (like cannas and bananas) will grow in any good soil, but this mix would be best.
Interesting advice on filling planters here:
https://jayscotts.com/blog/filling-large-planters/
You can choose light or heavy fillers for large planters
Light:
Compostable
· Coconut fiber
· Paper cups
· Wood chips
· Sphagnum moss
· Recycled cardboard pieces
· Pinecones
Non Biodegradable
· Styrofoam peanuts/ packing peanuts
· Crushed soda cans
· Foam blocks
· Plastic milk jugs
· Plastic bottles/ plastic containers
· Bubble wrap
· Empty potting soil bag
· Empty plastic
Heavy:
Compostable Materials
· Broken ceramic
· Wood logs
· Tree branches
Non-Biodegradable Materials
· Large rocks
· Broken pieces of concrete
· Gravel
· Sand
· Glass pebbles
· Empty beer or wine bottles
· Old golf ballsConsider whether you want to move the planters and whether you will need to divide the plants and repot e.g. bamboo.
https://jayscotts.com/blog/filling-large-planters/
Light:
Compostable
· Coconut fiber
· Paper cups
· Wood chips
· Sphagnum moss
· Recycled cardboard pieces
· Pinecones
Non Biodegradable
· Styrofoam peanuts/ packing peanuts
· Crushed soda cans
· Foam blocks
· Plastic milk jugs
· Plastic bottles/ plastic containers
· Bubble wrap
· Empty potting soil bag
· Empty plastic
Heavy:
Compostable Materials
· Broken ceramic
· Wood logs
· Tree branches
Non-Biodegradable Materials
· Large rocks
· Broken pieces of concrete
· Gravel
· Sand
· Glass pebbles
· Empty beer or wine bottles
· Old golf balls