16x20x4 (3 5/8) Pleated MERV 12 Air Filters 2 Pack growing-media A high performance drainage layer

A high performance drainage layer is especially important if your plants are grown in plastic containers or with saucers underneath which can trap excessive moisture and create a soggy root zone

A low-linting

24"-36" for seedling

Use as a nutrient or supplement during the vegetative stage of plant growth

Field growers should apply Z7 at first planting and whenever possible thereafter

16x20x4 (3 5/8) Pleated MERV 12 Air Filters 2 Pack growing-media A high performance drainage layerImportant Note: Almost ALL furnace filters have a different "actual size" than the nominal size printed on the air conditioner filter. It's best if you measure your air filter for the EXACT size and compare it to our "Actual Size" and then you can be sure your A C air filter fits! With the 4" and 5" air filters there is a wider variance between the nominal and actual size depending on the manufacturer. If you are replacing a 4 3 8 depth 16x20x4 filter