Maximum Yield Australia/New Zealand March/April 2021 | Page 38

VERTICAL SYSTEMS
The most commonly used vertical hydroponic systems are those that either incorporate a tower , column , or stacked design where plants are positioned around the sides often from floor to just under the light source , to staggered systems that allow for a more uniform pattern of light interception . Where the light source is only coming from directly overhead , planted tower or columns often run into problems with insufficient light in the lower levels of the system while plants at the top may end up too close to the light source . With indoor vertical systems , and in some greenhouses , the uneven light interception can be assisted with the use of supplemental side lighting , however , this also takes up additional space . Vertical systems , however , can be successfully used under high natural light conditions provided the design takes light penetration , the effect of shading of upper plants on lower plants , and other factors such as air flow into account . While vertical systems do significantly increase the plant density per unit area , if light is insufficient on the lower levels of these systems , produce quality can be reduced and overall yields will be lower than expected . Some crops , like strawberries , may seem well suited to a vertical or tower system , however , if light levels are limiting on the lower levels of the system , berry quality in terms of brix and flavour will suffer .
Vertical and horizontal space can be optimised under artificial lighting .

“ Where the light source is only coming from directly overhead ,

A moving lettuce production system allows access to light for all plants .
planted tower or columns often run into problems with insufficient light in the lower levels of the system .”
Tiered lettuce production systems can be used in high light climates to maximise growing area .
TIERED SYSTEMS
Staggered or tiered systems , often housing NFT channels , are another way of making use of vertical space , and have fewer issues with light penetration and intensity on the lower levels . Tiered systems are commonly used for small plants like lettuce , salad greens , strawberries , and culinary herbs . Basic-tiered systems using only natural light or overhead lamps may have between two to four tiers depending on crop type and light intensity . NFT channels may be in tiers directly one above the other or staggered into an ‘ A frame ’ or similar arrangement to maximise light interception on each tier . Indoor gardens have the advantage that lighting can be flexible within the tiered system , so plants are not solely dependant on a single overhead light source in the growing area . These systems have long been used for raising hydroponic crops such as seedlings , vegetative propagation , microgreens , baby salad leaf , and other short and compact plants . Each shelf or tier has hydroponic production channels or shallow beds with an overhead light source attached to the underside of the next tier frame . Light levels need to be carefully controlled and assessed for these types of systems to provide sufficient and even intensity over the entire cropping surface without the risk of burning sensitive leaves as they grow upwards towards the light source . Tiered and staggered systems also need consideration when it comes to plant access — growers need to be able to harvest , plant , maintain , and view all the plants on each tier which can become increasingly difficult if the tiers are shallow . Another important factor with tiered systems is air flow and many poorly designed systems can become overcrowded to the point where air circulation is inhibited .
38 Maximum Yield