The "proof is in the pudding" when it comes to evidence of Air Root Pruning of bags on the Drain Spacer Sheet.

An application to test the effects of the Drain Spacer Sheet under bags was applied to a system in Kent, whereby a double row of bags (side by side) was laid.  All component inputs, including substrate and plant type, were identical.  All the bags were irrigated from a common valve, and received the same watering and feed applications.  One side of the row comprised bags placed directly onto plastic sheeting, as was common practice on the farm at the time, and the other comprised bags placed on Drain Spacer Sheets.  Within weeks of planting the Air Root Pruning benefit of the Drain Spacer Sheet was clearly evident.

Bags directly on plastic:

Bags on Drain Spacer Sheets: