How to Make Indoor Vertical Gardens Actually Work 1

Wednesday, June 10th, 2015
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As LED lighting and recycling efforts become business as usual, companies are looking to mother nature to further build upon their green requirements.

The vertical garden industry is booming as a result, beautifying building facades and vastly improving the indoor environment.

In the thick of this movement is University of Sydney alumnus Chris Wilkins, founder of the start-up company PodPlants.

“Currently over 28 per cent of businesses supporting the construction industry have a focus on green building practices and report that they are doing about 60 per cent of their projects green,” Wilkins said.

According to the World Green Building Trends Smart Market Report, this is up from 13 per cent in 2009 and is predicted to hit 51 per cent within three years.

This rise isn’t unexpected, as plants are proving to be quite powerful from an environmental perspective. They have been shown to help improve the health, well-being and productivity of a building’s inhabitants.

In Australia alone, the Department of the Environment state that Australians spend 90 per cent of their time indoors, whether in homes, cars, workplaces or entertainment spaces.

From an economic perspective, the CSIRO estimates that the cost of poor indoor air quality in Australia may be as high as $12 billion per year.

Wilkins, who regularly consults with leading architects around Australia on ways to include biophilic design principles into their projects, said there are the three key benefits to indoor plants:

Air Quality

“They improve air quality by consuming carbon dioxide removing volatile organic compounds like formaldehyde and benzine, and they help regulate the temperature and humidity – which is not only good for our skin, eyes and throat, but is a key factor for overall ‘Indoor Environmental Quality (IEQ) rating,” he said.


Humans naturally connect to plants. In healthcare environments, biophilia strategies have been linked to faster patient recovery while offerig thereaputic benefits. In aged care facilities, they can create a serene environment.

Biophilia is shown to provide emotional and therapeutic benefits to humans

Biophilia is shown to provide emotional and therapeutic benefits to humans

“For more than 200,000 years, humans have been dependent on the natural environment for the basics needed for survial (food and shelter to mention just a few),” Wilkins said.

“This evolutionary reliance is hardwired into our emotional brain – we feel calm and happy when we are in a natural healthy landscape where plants are in abundance. Adversely, our emotions motivate us to find greener pastures when we are in a deserted or uncertainly environment. The brain produces stress hormones when it perceives the environment to be unsustainable for human survival.”

Wilkins noted this theory could explain why vacations to country retreats and beaches are seen as stress relievers.

Health and Well-being

Indoor plants in work spaces do wonders for workers’ well-being and performance.

“Smart businesses are strategically using indoor plants to reduce absenteeism and ‘presenteeism’ – being physically present but mentally absent,” Wilkins said.

He said indoor plants can help create a workplace that is “physically comfortable, has air which has sufficient oxygen in it to stay awake and does not suffer from what leading researcher Dr Fraser Torphy has described as ‘the narcotic effect of CO2′ (making employees) emotionally comfortable.”

This is turn can increase productivity, memory function and attention span.

Despite the mounting evidence of the benefits of indoor plants, maintenance concerns make some resistant to the idea. Proper soil conditions, water and irrigation are necessary to keep the plants alive and aesthetically pleasing.

There are three current systems on offer, all of which face irrigation problems:

  1. Hanging pot plants on the wall and use a drip irrigation hose going from pot to pot
  2. Milk crate systems where a plastic crate is filled with fabric and growing media, with plants grown out through the front of the crates
  3. Geotextile blankets fastened to the wall with soil filled pocket holding plants.

“The biggest challenge facing the vertical gardening industry at present is how much to water the plants and how often,” said Wilkins. “Too much and the plants will die of ‘root rot’ caused by suffocation and resulting in a bacteria growing on the roots, too little and the plants will dehydrate and die.”

It was this challenge that prompted Wilkins and his team to develop an ‘aeroponic green wall system’ by essentially using medical technology to grow PodPlants.

The technology was originally designed to improve yields and growth rates in agriculture by improving the root formation of the plants but their decorative vertical garden gained commercial interest.

The lightweight system is made from recycled materials and is portable and soil-free. The “aeroponic” part sees the plants watered by small droplets of water that are suspended in the air.

 PodPlants Aeroponic system consumes less that 1/10 the amount of water of traditional systems.

PodPlants’ aeroponic system consumes less than one tenth as much water as traditional systems.

The roots hang inside a sealed panel while the foliage grows on the outside.

“(It’s an) environment for the plants where the roots have 100 per cent access to both water and oxygen at the same time – by watering them with mist – this eliminates the problem completely,” Wilkins said.

This means clients are not replacing dead plants each week and do not waste nutrients due to evaporation or runoff.

“We recirculate the water and therefore only consume about one litre per day for every 450 plants (2.5 square metres). This means we only need to refill the water monthly and it takes less than 10 minutes per unit,” said Wilkins.

Like all vertical gardens, plant selection is key. Plants that don’t require soil remove much maintenance and offer the following benefits:

Air plants could live longer than other plants

“When in a controlled environment, I would expect that the lifespan would be equal.” Wilkins said. “However, because soil plants die so regularly due to the watering requirements being difficult to get right consistently, PodPlants plants do live longer because of the reduced mortality rate.”

More plant varieties on a given wall

“Most plants that can be grown aeroponically can also be grown in soil and vice versa; however, combining species that like it dry and species that like it wet can be a challenge when you have just one big irrigated textile on the wall,” explains Wilkins.

Aeroponic technology also allows more combinations of plant species that have different requirements due as water and oxygen levels can be altered easily.

Wilkins and his company are now working on a domestic edible kitchen system and an outdoor version.

Edible foliage is set to be the next stage of indoor greenery, leaning on urban farming methods in cities.

Wilkins plans to provide to the agritech industry and to support social enterprises which are helping to address food security issues.

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  1. Naomi Sachs

    Great article. I would love to know about infection risk – many hospitals want to incorporate greenery indoors but resist due to infection control issues (especially Legionnaire's Disease). Does the system that Wilkins and team developed also reduce the risk of bacteria that breed in standing water, and aerosolized water that would reach patients? Thank you!