Plantstraws Size Guide

Size guide:

20 cm (8 in) For pots up to 16 cm (6 in)high, or all setups with height difference up to 13 cm (5 in). 

30 cm (12 in) For pots from 11 to 26 cm (4.5 to 10 in) high, or all setups with height difference up to 23 cm (9 in).

However - its OK to play around!