resin.
This is the easiest system to set up.
A container with a well drained mix
is placed in the tray and water is
added.Water can be added through the tops of
the containers or the water can be poured
into the tray. Gardeners use several
methods to maintain this system. The water
level should be maintained at a constant
level by adding water as it is used up.
Most American gardening books advise
that when roots sit in water they may be
damaged. In Europe however, containers
incorporating the reservoir system are sold
as standard items in plant stores. As long
as the roots come in contact with air
containing oxygen, their needs are met.
A ball valve similar to the ones used in
toilets are sometimes used to automate this
system. When the water level falls, the
valve opens up filling the tray to the desired
height. When several trays are being used,
the valve sits in its own container and