26x30x1 MERV 14 Plus Carbon AC Furnace Filters 6 Pack grow-system/-trays/-reservoirs It will remain effective for

It will remain effective for approximately 10-12 weeks and can be re-applied at half the initial rate to extend root protection in the field or when transplanting to a larger container

The entire line of GROW

Non-slip handle grips provide excellent control and comfort on the job

Home Garden Grower

26x30x1 MERV 14 Plus Carbon AC Furnace Filters 6 Pack grow-system/-trays/-reservoirs It will remain effective forNordic Pure Custom MERV 14 Plus Carbon air filters are made based on the actual measurements so be sure to measure your current filter to get the EXACT dimensions before ordering. As with all Nordic Pure filters, the effective life of your filter depends on the environment in which you live. We recommend changing 1 and 2 filters every 30 90 days. Our 4, 5 and 6 inch thick filters could last up to 6 months. EXACT MEASUREMENT: Furnace and air condition