To achieve maximum yields it
is essential to maintain a plant's shape and remove any unnecessary or
damaged growth. This is most important when growing indoors under
artificial lighting.
Shaping plants
When growing under artificial lights (HID or fluorescent), light will be
best utilized by keeping plants short. This can be achieved by
pruning and 'training':
Pruning: Once the
initial 3 or 4 true leaves have formed, a plant can be made to possess 2 or
more main stems by removing the 'terminal
growing tip' (Fig 11.7a). The new main stems will grow from the 'axillary
buds' located at the remaining
leaf nodes (Fig 11.7b). Apart from being shorter than a single stemmed
plant (of the same age), multiple stems allow a classic "goblet" shaped
structure to grow (Fig 11.8a). This shape generally permits better airflow and
light penetration throughout the foliage.
Major 'structural' pruning should
only be conducted during the vegetative phase. Unless there is
over-crowded or damaged growth (see below), avoid stressing plants by
pruning during flowering. If plants are becoming too tall, retrain the
branches by bending them horizontally
either under netting (Fig 11.8b) or along string .
Training: Upward growth can be restrained by erecting netting
at an appropriate height. Once plants hit the netting they can either
be:
+ Trained
to grow horizontally (Fig 11.8b). Notably, many plant species will
respond by producing floral growth at the point where the stem is bent
beneath the net .
+ Allowed
to grow through the netting (Fig 11.8a). However, if they grow too tall they can
be bent down under the netting.
