16x20x4 (3 5/8) Pleated MERV 12 Air Filters 2 Pack growing-media The nymphs are also transparent

The nymphs are also transparent and difficult to see without a microscope

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 property that is essential if automatic irrigation systems are used

24"-36" for seedling

- Mixing bucket and other supplies

16x20x4 (3 5/8) Pleated MERV 12 Air Filters 2 Pack growing-media The nymphs are also transparentImportant 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