A fiberglass, perforated “sub-floor” is positioned 3″ above the liner floor. This partition allows water to drain into the reservoir below. The reservoir acts as an irrigation system by watering the plant’s root ball. The sub-floor is permanently laminated into the liner but upon request may be made removable. An optional drain can be installed in the sub-floor to ensure that water does not rise above this level so there is never any concern of overfilling. See the “Liner Types” page for more information on drains.
For typical irrigation, watering thoroughly from the top to be sure all the soil has been moistened and the water reservoir is full. Begin normal water frequency (once every one to two weeks). Let the plant use the water retained in the reservoir before watering again.
Sub-irrigated foliage benefits from “lighter” mixes with larger particles and more air space. Prepare the soil above the sub-floor with coarse perlite. Filter fabric may be used at this point to prevent soil and roots from entering the reservoir.