IWS Standard Flood & Drain Grow System (10.5 Litre Punch Pots)The IWS Flood & Drain The Great British Grow System that Delivers Massive Yields in Larger Indoor Gardens The IWS Flood & Drain is a fully automated feeding system that takes the strain out of tending to larger numbers of plants. This system has been a customer favourite for decades, and there are very good reasons for that: it's simple to set up and run, it makes tending to commercial scale gardens quick and easy, it allows you to control feed times