# Styrofoam Usage Question **URL:** \ **Category:** Factual Questions\ **Created:** [June 14, 2026, 3:28am UTC](https://boards.straightdope.com/t/styrofoam-usage-question/1030886 "2026-06-14T03:28:22Z")\ **Posts on this page:** 15\ **Page:** 1
**Author:** ![19USMC69](https://avatars.discourse-cdn.com/v4/letter/1/ac91a4/32.png) [@19USMC69](https://boards.straightdope.com/u/19USMC69)\ **Post date:** [June 14, 2026, 3:28am UTC](https://boards.straightdope.com/t/styrofoam-usage-question/1030886/1 "2026-06-14T03:28:22Z")
We’ve got a large pot in our yard, approximately 20” in diameter and about the same deep. What’s planted in it requires very little soil. Is it problematic to fill much of the void with styrofoam to save weight and soil? From what I’ve read, and for all intents and purposes it doesn’t decompose. Will it break down in some way to plug up the pot’s drain holes. ---
**Author:** ![nearwildheaven](https://avatars.discourse-cdn.com/v4/letter/n/90db22/32.png) [@nearwildheaven](https://boards.straightdope.com/u/nearwildheaven)\ **Post date:** [June 14, 2026, 4:15am UTC](https://boards.straightdope.com/t/styrofoam-usage-question/1030886/2 "2026-06-14T04:15:26Z")
What kind of plant is this? I personally wouldn’t recommend using Styrofoam. If you can get cornstarch pellets, or something similar, something that is biodegradable, that would work better. ---
**Author:** ![DPRK](https://avatars.discourse-cdn.com/v4/letter/d/4491bb/32.png) [@DPRK](https://boards.straightdope.com/u/DPRK)\ **Post date:** [June 14, 2026, 4:59am UTC](https://boards.straightdope.com/t/styrofoam-usage-question/1030886/3 "2026-06-14T04:59:55Z")
Can’t you use perlite? ---
**Author:** ![Kent\_Clark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kent_clark/32/105_2.png) [@Kent\_Clark](https://boards.straightdope.com/u/Kent_Clark)\ **Post date:** [June 14, 2026, 3:50pm UTC](https://boards.straightdope.com/t/styrofoam-usage-question/1030886/4 "2026-06-14T15:50:28Z")
Styrofoam won’t break down, but it will crumble, and it’s very possible some of the bits that crumble will plug up your drainage holes ---
**Author:** ![19USMC69](https://avatars.discourse-cdn.com/v4/letter/1/ac91a4/32.png) [@19USMC69](https://boards.straightdope.com/u/19USMC69)\ **Post date:** [June 14, 2026, 6:27pm UTC](https://boards.straightdope.com/t/styrofoam-usage-question/1030886/5 "2026-06-14T18:27:34Z")
Thanks for the replies. I’ve since learned that styrofoam is not a good idea for a variety of reasons. Any thoughts on aluminum soda cans or used capped plastic bottled water containers? . ---
**Author:** ![Darren\_Garrison](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darren_garrison/32/92_2.png) [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)\ **Post date:** [June 14, 2026, 7:48pm UTC](https://boards.straightdope.com/t/styrofoam-usage-question/1030886/6 "2026-06-14T19:48:15Z")
If reducing weight is an important factor, I don’t see why layering water bottles in the bottom wouldn’t work. Or you could use [ping pong balls](https://www.amazon.com/RWHXRWY-Colorful-Entertainment-Projects-Decorations/dp/B0F1MBM5BM?dib=eyJ2IjoiMSJ9.WosJREqJbvSG3qvvLw55-GBg46ka_J6Hzl0eSc_qbscN6K3kL_XVSEH6UGgtYYd5W4C--vXauIBHKnOl2lGs5aHPCw0zDrX66TAAZ_evQrNYicICw3xivKCQ59IFdByNYF1gs0L9Yykf39rNlSsi5-aPyE7MyhuZaj9WSe5RCaDs7U6O5xFA1T1Hj67aDj-2W8uMKaegL1lxhBsI30JuDA.Tyw7zBwKucFECZplPojtpLMWlJgqRBpaSMi68aLpC5U&dib_tag=se&keywords=ping+pong+balls+bulk&qid=1781465911&sr=8-15) and have them to raise a sunken ship if you needed to. ---
**Author:** ![mixdenny](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mixdenny/32/2962_2.png) [@mixdenny](https://boards.straightdope.com/u/mixdenny)\ **Post date:** [June 14, 2026, 7:48pm UTC](https://boards.straightdope.com/t/styrofoam-usage-question/1030886/7 "2026-06-14T19:48:47Z")
The classical fill is large stones but that adds a lot of weight. Pumice rocks are fairly light. I think sealed bottles would work fine. ---
**Author:** ![Dewey\_Finn](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dewey_finn/32/4222_2.png) [@Dewey\_Finn](https://boards.straightdope.com/u/Dewey_Finn)\ **Post date:** [June 14, 2026, 7:57pm UTC](https://boards.straightdope.com/t/styrofoam-usage-question/1030886/8 "2026-06-14T19:57:18Z")
How about simply an upturned smaller flower pot? ---
**Author:** ![Apodder](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/apodder/32/17727_2.png) [@Apodder](https://boards.straightdope.com/u/Apodder)\ **Post date:** [June 14, 2026, 9:33pm UTC](https://boards.straightdope.com/t/styrofoam-usage-question/1030886/9 "2026-06-14T21:33:09Z")
Actually, most of my big pots have big chunks of Styrofoam and empty plastic water bottles in them for just that purpose. Been in there for a few years and no issues yet. ---
**Author:** ![TRC4941](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/trc4941/32/6792_2.png) [@TRC4941](https://boards.straightdope.com/u/TRC4941)\ **Post date:** [June 15, 2026, 1:50pm UTC](https://boards.straightdope.com/t/styrofoam-usage-question/1030886/10 "2026-06-15T13:50:00Z")
I’ve used the empty plastic planters that plants come in when you purchase them. I sometimes rummage through our recycling bin and find plastic bottles/containers and use those. ---
**Author:** ![jnglmassiv](https://avatars.discourse-cdn.com/v4/letter/j/f07891/32.png) [@jnglmassiv](https://boards.straightdope.com/u/jnglmassiv)\ **Post date:** [June 15, 2026, 2:17pm UTC](https://boards.straightdope.com/t/styrofoam-usage-question/1030886/11 "2026-06-15T14:17:12Z")
> [@19USMC69](#): > > used capped plastic bottled water containers That’s what I’ve used, it works great. Mine were a little thicker, for carbonated mineral water, and, aside from the labels, barely aged after a few years. ---
**Author:** ![Crafter\_Man](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/crafter_man/32/458_2.png) [@Crafter\_Man](https://boards.straightdope.com/u/Crafter_Man)\ **Post date:** [June 15, 2026, 2:41pm UTC](https://boards.straightdope.com/t/styrofoam-usage-question/1030886/12 "2026-06-15T14:41:55Z")
> [@Apodder](#): > > most of my big pots have big chunks of Styrofoam and empty plastic water bottles in them for just that purpose. Been in there for a few years and no issues yet. While I don’t see a problem with using Styrofoam, I think extruded polystyrene (XPS) would be a better choice, as it’s more “waterproof” than Styrofoam. ---
**Author:** ![Dewey\_Finn](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dewey_finn/32/4222_2.png) [@Dewey\_Finn](https://boards.straightdope.com/u/Dewey_Finn)\ **Post date:** [June 15, 2026, 7:54pm UTC](https://boards.straightdope.com/t/styrofoam-usage-question/1030886/13 "2026-06-15T19:54:51Z")
Googling, the kind of foam used in product packaging is expanded polystyrene while Styrofoam is a brand name used for insulation boards made of extruded polystyrene. ---
**Author:** ![Crafter\_Man](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/crafter_man/32/458_2.png) [@Crafter\_Man](https://boards.straightdope.com/u/Crafter_Man)\ **Post date:** [June 15, 2026, 8:14pm UTC](https://boards.straightdope.com/t/styrofoam-usage-question/1030886/14 "2026-06-15T20:14:30Z")
Reading the Wiki page on Styrofoam, you are correct, and I wasn’t aware of that! But in common usage, people rarely call XPS “Styrofoam.” Instead, “Styrofoam” is used when referring to the white stuff (EPS), and yet that appears to be incorrect. Interesting! ---
**Author:** ![Dewey\_Finn](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dewey_finn/32/4222_2.png) [@Dewey\_Finn](https://boards.straightdope.com/u/Dewey_Finn)\ **Post date:** [June 15, 2026, 11:28pm UTC](https://boards.straightdope.com/t/styrofoam-usage-question/1030886/15 "2026-06-15T23:28:05Z")
To clarify the abbreviations you used, XPS is extruded polystyrene while EPS is expanded polystyrene.