Container size: Ensure growing
containers provide ample room for root growth. Root ‘hairs’ are
responsible for the majority of nutrient uptake and their growth depends
upon there being
sufficient space. If root growth is restricted, the plants may never reach
Drainage: To aerate the root zone and
help prevent disease problems, the root zone must drain completely
following each feed:
- Ensure the trays and channels have
suitable slope (gradient 1:40).
Position drainage outlets as low as possible on the container’s sidewall,
or preferably in the base.
- Place filter material (e.g. mesh) at
the entrance to the outlet to help prevent blockage from roots or medium.
- Where feasible, use pots with mesh
sidewalls or bases. These encourage aeration of the root zone, are less
restrictive to outward root growth, and will ensure optimum drainage.
Color: As with reservoirs, black
and/or opaque plastic is best. This prevents light transmission and
reflection which can harm nutrients and promote the growth of fungus and
Light exposure: Where possible, cover
the surface of the medium to prevent light from reaching the roots.
Plant spacing: Where a single growing
container contains multiple plants, such as in an NFT channel, position
plants far enough apart from one another so that their roots do not become
entangled. This facilitates the easy removal of plants for harvesting
(e.g. lettuce) or for those that are diseased.