Environmetally friendly and economical.
Please use replaceable core refills.
The inner core of SUSTEE is made of natural fibers and can be consumed by microorganisms.
The state of the soil is a factor, but it can be said that the core has to be replaced when it stops turning blue after watering (approximately after 6-9 months).
 
Changing the core is done in two steps.
It is easy and can be done by anyone.
Pull SUSTEE from the pot and follow the instructions on the image above.
If dirt has accumulated in SUSTEE clean it before you insert a new core.