What is the fine-grained topic of the following text: Available in either a tray of 24 cubes or a bag of 100 loose refills, Fleximix Root Riot Organic Starter Cubes are one of the best rooting mediums we have come across - rooting successfully up to two days earlier than rockwool during tests. Only return the topic.
Fleximix Root Riot Organic Starter Cubes Product Review