White garbage bag covers for rockwool?

[rimbaegeus]

Hey, is it a bad idea to cut up white garbage bags into 4" squares to put on top of my rockwool cubes (with a hole in the center)?

[Zandor]

Just make sure NO light get's through. Panda plastic is about the only white one I know that works well and blocks the light. Black pond liner works great too bty.

True black will absorb some heat but only early on in the cycle when the roots like warmer temperatures anyway. Once the folage fills out then it's fine.