One of the things I have done over the course of the last year is to move away from using plastic pots to using different sizes of polystyrene cups.
These poly-cups are used by take-away businesses and I have to make the holes in the base but
there are a number of reasons for the move away from plastic...
a) cost... a 7cm plactic pot cost me 15p, while I can buy 25 poly-pots for £1.
b) being polystyrene the cups warm up a lot quick and hold the heat better. This helps the roots dry out quicker and reduces roots rotting, which is a problem if you have a habit of over watering.
c ) these poly-pots can be obtained in shallower half sizes which are great for clumping species like glassiii, prolifera and members of the Stylothelae who do not produce large root balls.
d ) the tall cups are 7cm diameter at the top but taper in more at the base and are about 25cm deeper and I have found plants of the Ancistracanthae have grown a lot better in these cups.
e) being white the cups are photo-reflective, throwing light back out onto the plants.