Polyester as growth medium

Hi I'm a long time grower. About 50yrs.
Last 20yrs pretty well all hydro/indoor.
I have an insulation co. and am always looking at ways to utilise waste.
Q. Has anyone tried polyester insulation (basically it's recycled coke bottles [PET] spun into threads) as a growth medium.
I'm about to give it a go so will keep you posted. Just thought I'd ask and NO, I don't want to know about rockwool and as for glass fibre, well more fool you.
Thanks

Cool idea! Definitely following this one.

I want to see man

It's not going to cause issues with pH or anything, I have heard of it being used as a replacement for rock wool starter cubes but nothing about it being used as a sole medium for mature plants. You should try a test plant somehow and see how it works. I would treat it like any inert hydro medium and irrigation frequency would be the first thing to figure out. I can imagine compaction will be a thing as the plant grows and gets heavier, the roots would be filling up the air spaces so I am not sure it would end up with as much air space as perlite after the roots pack the container. Interested in your findings, I have wondered about using poly fill bats to lay in a flood and drain tray with plants hanging above in net pots from a cover.

Something similar was developed about 8-10 years ago. Pre-cut into cubes. I use them. I don't think they're still available

I work with plastics, but i havent studied material sciences or stuff, but i do know a thing or two about them.

First there are better options than mashed soda bottles. PET is pretty hard, so if you have some PET shread, it could easily damage the roots. Also there are other plastics that are more biocompatible. It is possible that over long periods of time, they could start to compose and allow the plants to eat the plastic microparticles.

Polypropylene would be a better budget plastic. And it would make a bit softer shred, but shred might be a bad idea anyways, unless you can make it reaaaaaally fine so that its soft.

But what i really recommend if you are planning to reuse them, is to buy some PVDF granules. It is basically chemically inert plastic and you can even have some inside of your body for hundreds of yours before it leaks out anything. It is a lot more expensive than PP(polypropylene) or basic plastics, but if you dont needs hundreds of litres and you think it as long term investment, it could be worth it. Or maybe test with PP first and then get PVDF if it works. PVDF i can assure your grandchildren could still safely use if they wash them after each grow(it would be dishwasher safe or you could even sterilise it with radiation or with nearly any chemicals/solvents in under 200C degrees and PVDF could handle it), ofc if there were no impurities in producing it in the first place.

You can get plastics in these granule form for very cheap in bulk. These granules are what are being used in plastics industry in injection moulding or you could make 3d-printing filament from these for example. I think the granule form would be pretty optimal for growing hydro. Plastic shred would likely just hurt the roots.

Mine are from Suretogrow, but the company did not make it. Excellent for clones, not sure I can do seeds with them, Th pics I posted all failed. Started 3 new seeds in them yesterday

I've done a rockwool run with 3" cubes sitting ontop of poly weave fabric I got a wallyworld. The roots grow under the material. If you have spare leftover poly I'd say go for it. I wouldn't run out and shell out coin to try it though. It wasn't really too impressive and I had way more roots in a bed of hydroton pebbles.

It's veen a very very long time but, i hope you've had successful results, and I look forward to any updates or insights you can share!

Your innovative approach to utilizing waste and exploring sustainable alternatives for growth mediums is impressive, even though this thread is a few years old. Using recycled polyester insulation, derived from PET (polyethylene terephthalate) found in coke bottles, is a unique idea.

Now days you can find ways to recycle your PET into spools of filament, so you can print out hydroponic system parts, netcups, etc.