Vert farming has become a catch cry in the past three years among advisers and futurists looking to it as a means of answering the challenges of land loss to urban development and population growth.
The farming method involves an amassing technology for large-scale fruit and vegetable production using sophisticated greenhouse methods to achieve a high level of productivity thanks to nutrient controls, lighting levels temperature, air and growing medium composition.
NZ’s population is expected to reach five million by 2020 with pressure on valuable soil areas only likely to continue, Horticulture NZ environmental policy adviser and Nuffield Scholar McClung says.
In the Auckland region alone 30% of high quality horticultural soils have been lost in the past 20 years to housing and tar seal.
Land and suitable soils might exist in places beyond traditional produce areas like Bombay, south of Auckland, but the climate is not always as forgiving in those other areas for year-round production.
“For instance, Pukekohe supplies the market with Christmas new potatoes while Oamaru is famous for Jersey Benne potatoes, harvested around November.”
By 2043 demand for produce in NZ is estimated to be 33% higher than today while any further conversion of valuable land to housing will only further affect food production.
McClung’s work was prompted by sustainability strategist Henry Gordon-Smith being reported by KPMG that NZ should focus on vertical farming as an answer to its growing produce constraints.
McClung said her work reveals, however, that despite the claimed productivity gains vertical farming can deliver, it is relatively constrained to a few leafy salad and herb crops.
They have to be fast growing, subject to one month harvest time and require only a relatively low-light density.
Typically, they include crops like tomatoes, peppers and lettuces.
But the technology cannot grow crops like rice, corn and potatoes that are staples for millions around the world.
Viewing vertical farming through environmental, social and economic benefits, McClung notes the method claims increased yields over traditional horticultural methods while soil degradation and land use area are significantly reduced.
From a social perspective the technique offers opportunities to develop new careers in agriculture, given the complex interweaving of disciplines that include computer programming, agronomy, economics, biosecurity and design.
But in her global examination of vertical farming enterprises McClung could not find any that stand on their own feet commercially.
“It seems they have all been started up with investor or government funding and as soon as those investors walk away they do not seem to be able to sustain themselves.”
She suspects project complexities and a developing field of technology might mean it is another decade or more before the technology is fully viable.
Meantime, her advice is for NZ to keep a watching brief on the technology tempered by the knowledge most crops it was can grow are predominately eaten domestically in NZ and have no likelihood of replacing NZ’s high value horticultural produce.
Instead, McClung advocates promoting greater awareness to New Zealanders about the value of the horticultural land this country is fortunate to have. That includes Hort NZ advocating for a National Policy Statement on protecting productive land and high quality soils.
It should be part of an overall national policy on food security.
“A national policy on food security is something that the United Kingdom, Europe and Australia all have but we do not. A policy statement on protecting valuable soils would be part of the jigsaw puzzle that sits under that.”
She said nationally the country risks being complacent about food security with many people thinking NZ feeds 40 million people.
“But we have to ask ourselves, what is it that we are feeding those people.
“We have sectors like the pork sector where almost 60% of product is imported. We already consume 90% of the vegetables we grow.
“Having a policy on food security will help ensure we can provide ourselves with a balanced diet in years to come.”
