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FEATURE

ROOFTOP HOPS

Khaya Maloney qualified as an engineer and today grows hops hydroponically
on the rooftop of Constitution Hill in Braamfontein, Johannesburg. He chose this
site to introduce an urban ecosystem of brewing into the inner city, as well as to
validate the history surrounding this iconic building.

n order to educate himself about
hop production, he joined an
Iincubation programme run
by Wouldn’t It Be Cool Incubator,
sponsored by various stakeholders
including Johannesburg inner city
partnerships, Jobs Fund, GWK as
well as SA Breweries, who own
all breeding rights for hops. He
also received support from the
Minerals Council South Africa and
was assisted by a Pretoria based
farmer, Gert van der Waal, who
mentored him and taught him
about the hops growing process.
The Minerals Council had a
similar initiative aimed at putting
greenhouses on rooftops and
Maloney approached them with
the idea of growing hops instead
of vegetables, using hydroponics.
The undertaking has created an
urban agricultural ecosystem by
repurposing rooftops to produce
crops for Johannesburg’s inner-city
residents.
Rooftop growing
Hops are a high value crop,
traditionally grown and harvested
once a year in George, Western
Cape, where climatic conditions
are optimal for them. Maloney has
been able to produce between
three to four harvests a year due
to the customised, controlled
conditions of the greenhouse he
has set up, and its ability to be
manipulated for ideal growing
conditions. He describes the project
as a commercial experiment and a
combined business and agricultural
undertaking.

The following information is
relevant to the horticultural side of
the business:

Adequate roof space is required, as hops can grow as much as 8 cm in a day

• Johannesburg has 12-14 hours of • during the flowering stage of the grow temperature. They are connected to the
sunlight daily, in contrast to George cycle, the hops are manipulated or ‘tricked’ two CO extractor fans and pulsators
2
which has 16 hours, and therefore has by means of thick, dark curtains installed that have been installed to ensure that
to be supplemented by CFL lights that in the greenhouse. This process is known the ideal temperature (between 17ºC
are automated to turn on when the sun as photo-periodism; and 21ºC) is maintained. Temperatures
sets. This ensures that the plants get the • sensors are installed in the greenhouse must be kept fairly low to avoid fungal
required amount of light per day; which helps maintain the required infections to the plants;

10 Landscape SA • Issue 119 2022