Passive kits and systems consist of hand- or capillary-watering.
Hand-watering is exactly what it says – watering by hand. This method depends on how much effort the grower is willing to put in, but does not really offer much more than traditional fertilisation techniques.
Whilst capillary-watering can be achieved through a range of techniques – using a valve from a reservoir; having pots that sit on a regularly watered capillary matting; sitting pots in a shallow reservoir, where the capillary matting draws the solution up to the media; or placing individual pots in trays or saucers that the solution is put into. This is a simple, cheap and easy-to-maintain method, but can be prone to over- or under-watering.