“We can see and feel the impact climate change has had on the growth of our crops,” says Godfrey Leung Kwok-fung, founder of Living Farm, a community organic farm in Tai Po, in the New Territories.

Farmers are more sensitive to climate change, says Leung, and this summer’s crops such as cucumber, bitter melon, water gourd and hairy gourd have been the most affected.

“The more extreme weather we face, the less we have to harvest,” says Leung.

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Climate change poses a threat to global food security as soaring temperatures, extreme weather and water scarcity take a toll on crop yields.

A 2020 study in scientific journal Nature Sustainability estimates that yields of soy, maize, rice and wheat – the four crops account for more than 60 per cent of calories produced globally – will decrease as the planet warms. Weather-related shocks combined with higher oil prices will also lead to a surge in food prices.

In densely populated Hong Kong, where agricultural space is limited, more than 90 per cent of food is imported – mostly from mainland China. The city’s reliance on its neighbour was highlighted in 2022, when supermarket shelves sat empty of fresh food due to restrictions imposed on Covid-positive cross-border delivery drivers.

Agricultural innovation is vital to addressing the potential issues of climate change but there are some consumer-level ways to reduce one’s carbon footprint, such as demanding and sourcing produce from local farms instead of buying imported food.

Creating private gardens – on a balcony, terrace or rooftop – can also help: all that’s needed is a sun-filled space, a planter box as well as seeds and soil mixed in with some gardening know-how.

“Every plant has a preferred growing temperature, water amount, sun expo­sure and soil fertility requirement,” says Leung.

Karen Ng is a co-founder of Grow Something, a Hong Kong social enter­prise that transforms idle spaces such as rooftops and industrial buildings into gardens with a big-picture aim of reducing the city’s carbon emissions.

“More than 98 per cent of Hong Kong’s total vegetable consumption is imported, so growing your own reduces carbon emissions generated by transport and storage,” says Ng.

“There is nothing better than own-grown food that’s been produced not for its ability to travel thousands of miles – like the food in Hong Kong supermarkets – but for its taste, texture, colour and nutritional value. And they are free of chemicals,” says Hong.

As the city battles a mental health crisis, the benefits of gardening on well-being cannot be ignored, she adds.

“Interacting with nature reduces stress, and caring for plants is not only therapeutic but promotes physical and cognitive activity, especially among the elderly,” she says.

The first step to growing your own vegetables and herbs, says Hong, is identifying a space with sufficient sunlight. “Most plants need a minimum of four hours of direct sunlight to grow well, and fruiting plants need up to six to eight hours of sunlight per day.”

Hong Kong has two well-defined growing seasons: summer and winter. But climate change is also impacting prime growing times.

“The best time to grow vegetables in Hong Kong is typically between October to May, as the weather is more stable. But as we face climate change, this margin will narrow.”

Ng says early autumn is a good time to start planting herbs and leafy greens on a balcony.

“Herbs such as mint, basil, rosemary and thyme are recommended for half shaded balconies that don’t have direct sunlight while leafy greens such as lettuce and kale are recommended for balconies with at least half a day of direct sunlight,” Ng says.

“As for a helping hand, I suggest bokashi composting for home gardens because it can be done in an airtight container and kept indoors,” she says, referring to the method of fermenting waste into fertiliser developed by Japanese professor Teruo Higa in the 1980s.

A compost alternative, says Leung, is eco enzyme, a multipurpose liquid produced from the fermentation of organic waste such as fruit and vegetable peels. “It keeps pests away and increases photosynthesis, helping plants grow faster and healthier.”

Ng says there are many ways to keep insects and birds at bay, such as nets to protect crops and traps to catch insects. But a “sharing is caring” approach is best.

“Accept that growing is sharing with nature, so it’s OK if a caterpillar takes a bite of your vegetables.”

Hong says biodiversity is a key element to organic farming – a healthy garden ecosystem should have a balance between “the good bugs and the pests”. To tackle the latter, she recommends organic and natural pest control methods, such as using a home-made solution with garlic, chilli and vinegar, or a diluted neem oil solution to prevent pests such as aphids.

“We also recommend nettings and mesh bags to protect seedlings and fruits as these are highly vulnerable to birds, as well as various types of gourd and squash bugs.”

As for tips for budding green fingers, Leung says good soil is key – “composting is an effective way to manage garden and kitchen waste to create healthy soil” – while Ng says growing plants in season is vital.

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It may seem obvious but not everyone follows this simple principle.

“It is important to grow by the seasons, as plants will not only do poorly in the wrong temperatures but are more susceptible to pests and disease, which may spread to healthier plants,” says Hong.

“It’s also important to purchase seeds from the same climate, as many varieties may thrive well in one region but differing conditions such as temperatures and humidity will affect growth in another.”

Ng says a common mistake home gardeners make is checking on their planters a few times a day and only giving their plants a small amount of water each time.

“It’s not a good habit because a small amount of water only stays on the soil surface and evaporates so quickly that the roots are unable to absorb it.”

Other rookie errors that may lead to failure, adds Leung, include plants being too crowded, too much or too little water, not fertilising or trimming and forgetting to harvest.

Hong adds that growing your own food also raises awareness about healthy eating while practical experience with fresh food – growing, harvesting, identifying varieties in stores and farm stands, understanding seasonality, cooking – positively affects dietary habits.

“Studies show that kids are likely to eat their vegetables when they are involved in the process of growing them,” she says.

And if growing at home is not possible, she recommends joining a gardening community.

“The power of community is motivating and makes the process more enjoyable when you can invite others to your garden.”