The easiest way to create a high humidity environment is to use a humidity dome or propagator. This traps in moisture and prevents the cuttings from losing moisture to the air.
The Garland Propagators come with an adjustable vent at the top of the lid to aid in hardening off the clones once they have been in the propagator for a while. This promotes quicker root growth and minimises stress caused by sudden swings in environmental conditions.
The Garland Large Unheated Propagator is perfectly suited to hold a full tray of 24 root riot plugs or any other tray of the same size.