In-Between Hong Kong: Vertical Farming Reclaims the Voids of a Hyper-Dense City

Between the tightly packed tenement blocks of Kowloon City and Sham Shui Po, slivers of unused air separate buildings that were never designed to breathe. "In-Between Hong Kong" treats those voids not as leftover space but as infrastructure in waiting: vertical corridors threaded with hydroponic farms, suspended walkways, and communal platforms that give residents something the city has long struggled to provide, namely open space, fresh food, and the simple chance to see a neighbor face to face.

Designed by Xu Wang, this winner of the Parasitic Architecture competition responds to Hong Kong's intertwined crises of spatial scarcity, housing inequality, and food import dependence. Over 80% of the territory is mountainous or reclaimed land, leaving flat ground almost exclusively reserved for high-rise towers. In older districts, residents of subdivided flats and cage homes contend with minimal daylight, poor ventilation, and virtually no recreational ground. Wang's proposal refuses to accept those conditions as permanent, inserting a parasitic ecological system that transforms the residual gaps between Tong Lau buildings into productive vertical commons.

A Walkway That Grows Food Between Buildings

The central spatial experience is a narrow corridor flanked by hydroponic growing systems that rise several stories between existing structures. Figures pass through at ground level along a shared walkway while planter walls climb on either side, their leafy rows filtering light and softening the concrete canyon effect that defines these neighborhoods. The first image captures this interior courtyard condition: the passage is generous enough for pedestrian flow yet intimate enough to feel like a shared garden rather than a transit corridor.

Horizontal hydroponic beds, stacked in tight rows beneath a perforated ceiling, demonstrate how the system maximizes cultivation area within a minimal footprint. Soilless cultivation on cross-steel mesh frames means no heavy soil loads bear on aging masonry walls, and the perforated surfaces above allow diffused daylight to reach crops and residents alike. The result is an interior wall that doubles as a food production surface and an environmental buffer, improving air quality and regulating temperature for adjacent units.

Perforated Corridors as Social Infrastructure

A perforated metal floor stretches through one of the elevated corridors, with vertical hydroponic planters lining both sides as visitors move through. The perforation is functional on multiple levels: it allows airflow to circulate between floors, lets filtered light pass downward, and gives residents a visual connection to activity above and below. In a district where shared toilets and windowless circulation define daily life, this kind of spatial generosity is not decorative but corrective.

The corridor is deliberately positioned as a spatial buffer between the public planting zone and private residential units, a calibration that respects the privacy of subdivided flats while still inviting visual and social interaction. Wang zones these interfaces carefully: communal gathering areas for the elderly sit alongside passive leisure pockets and dedicated gardening platforms, structured to support routines from morning commutes to evening socialization. The parasitic addition does not demand that residents change their habits; it simply widens the field of what is possible within the existing urban fabric.

Modular Logic: Solar Panels, Growing Racks, and the Building Section

The axonometric drawing of a single module reveals the system's technical clarity. Photovoltaic panels sit on the roof, directly powering lighting and the nutrient cycles that feed the hydroponic crops below. Vertical growing racks fill the interior volume, organized so that maintenance access and crop harvesting can happen without disrupting pedestrian flow on the walkways. The module is repeatable, allowing the intervention to scale across different gap widths and building heights throughout Hong Kong's older districts.

An exploded axonometric pulls apart multiple floors of the complex, mapping how growing systems, circulation paths, and communal platforms interlock within the parasitic framework. Crop selection is tailored to Hong Kong's subtropical climate and culinary traditions: Chinese cabbage, amaranth, water spinach, and choy sum, all organized according to mapped growth cycles that stagger planting and harvesting throughout the year. The integration of solar energy, local food production, and social space within a single structural system turns what is typically wasted air between buildings into a functioning piece of urban resilience infrastructure.

Why This Project Matters

Hong Kong imports roughly 90% of its food. Its public open space per capita is among the lowest of any global city. And its aging Tong Lau districts, home to some of the most vulnerable populations, receive the least public investment. Wang's proposal does not solve all of these problems, but it identifies a precise architectural opportunity: the narrow gaps between buildings, currently doing nothing, could host a network of productive, walkable, breathable corridors that address food security, mental health, and community cohesion simultaneously.

What makes "In-Between Hong Kong" compelling beyond its technical ambition is its refusal to demolish. It is parasitic in the truest sense: it attaches to existing structures, feeds off rooftop solar energy, and grows food where only stagnant air existed before. The project offers a template for other hyper-dense cities facing the same converging pressures, proving that reclaiming space does not always require new land. Sometimes the space is already there, hiding in plain sight between the walls.

View the Full Project

About the Designers

Designer: Xu Wang

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Project credits: In-Between HongKong by Xu Wang Parasitic Architecture (uni.xyz).