SIP -- Sub-irrigated Planters = Passive hydroponics or self-watered containers?
Is the growing media the deciding factor? Media bed vs. raft bed, they are both present in hydroponic systems.
New to the forum here, so I'm a little late. But I wanted to chime in anyway.
An SIP is a planter that is watered, at least in part, from below the soil line. SIP is a description of the water
delivery mechanism. Nothing more. It might or might not be used in tandem with hydroponics.
Hydroponics is unrelated. Hydroponic growing refers to the method for delivering nutrients
, namely they are dissolved directly in the water. Any rooting medium would be completely inert and would serve as a structural mechanism only. Nutrients would not come from a soil product, but from the nutrient / water solution.
Soil based container growing is like eating your food orally & allowing your digestive system to process it. While hydroponic growing is like intravenous feeding.