Avoid non-food grade plastics such as PVC (#3) and Polystyrene (#6), as these may release harmful chemicals into the soil.

Food-grade plastics like HDPE (#2), LDPE (#4), and PP (#5) are already used in food packaging, so they are safe for container gardening.

Food-Grade Materials

Get a larger diameter for the water to flow around roots.

Minimum 4-Inch Pipe

PVC Pipe

Pipe with the label "NSF pw" is NSF certified for potable water use.

NSF Certifications

The actual designation you want on PVC in the US is NSF-61 or NSF-51. These are the National Science Foundation standards for potable water.

NSF Certifications

ADS Triple Wall HDPE Pipe

ADS Triple Wall HDPE Pipe 4-inch

Uses a Bell and Spigot joining system.

One one end of the pipe is a hub connector, the other end is plain.

Fittings

ADS Single Wall HDPE Bend ADS 4-in x 4-in 90 -Degree Corrugated Elbow Fittings

Does not work with ADS Triple Wall HDPE Pipe.

ADS 4-in x 4-in Corrugated Adapter Fittings

Does not work with ADS Triple Wall HDPE Pipe.

ADS 4-in x 4-in Corrugated Inside Coupling Fittings

Does not work with ADS Triple Wall HDPE Pipe.

ADS 4-in x 4-in Corrugated Cap Fittings

?

Silicone 180 Degree U-Bend 4-inch, 102 mm

Fits on the outside of the pipe or on the inside of the hub.

• Though it needs to be stretched to fit on the outside of the pipe.

• Only one side of the u-bend needs to be stretched. The other side fits in the hub.

May not be food safe if the silicone contains additives or fillers.

114mm max pipe clamps are too small! Get a size up.

Pipe Clamps