Backyard Aquaponics
A place to discuss aquaponics

Looking to make a growbed from large plastic sheets from Lowe's /home depot any plastics I should look out for?

Not sure on everything but to start with I would look for anything claiming to be fire retardant and or antibacterial/microbial. Although if you are planning to put media in it as apposed to a DWC, I would opt for pond liner. As you know it would be fish safe and thick enough to resist being punctured (normally) by your media of choice. I don't remember where at the moment, but I have read on a few threads where going cheaper using the plastic sheets ended badly.

These materials are fish and people safe.

In increasing expense:

LLDPE
LDPE
HDPE
Teranap
Fibre Reinforce LLDPE or LDPE
EPDM
Poly Urethane
Xavan (Xavon?)

I reccomend either Teranap, EPDM or Poly Urethane