Container size: Ensure growing
containers provide ample room for root growth. Root ‘hairs’ are
responsible for the majority of uptake and their growth depends upon there
being sufficient space.
Drainage: To aerate the root
zone and prevent disease problems, the root zone must drain completely
following each feed:
+ Ensure
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 prevent
blockage from roots, medium, etc.
+
Where feasible (e.g. ‘flood & drain’ systems), use pots with mesh
sidewalls and/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 because it prevents light
transmission and reflection which can harm nutrients, and promote the
growth of fungus and algae.
Light ingress:
In addition to that above, it is necessary to cover the surface of medium and/or prevent light ingress
into the
roots.
Plant spacing: Where a single growing container contains multiple plants
(e.g. NFT channel), it is desirable that spacing is sufficient such that
roots from adjacent plants do not become entangled. This facilitates
removal of diseased plants or plants that are ready for harvest.
Channel length: A compromise between NFT channel length and economic
considerations must be made. If channels are too long, plants at the head
of channels will show better results than those at the end.
