Tan Yifan

    cicitan2011@gmail.com

    ROOF gardening is a common part of sustainable urban planning. But for some eco-activists or quality-demanding foodies, roof gardening can be more practical if vegetables and other edible plants are included.

    He Daqiong, a representative from roof farming project No.1 Fresh, which was initiated by Shenzhen-based company Guangsangyuan, teaches people how to care for roof gardens and promotes the concept of planting what you can eat.

    An urban farming supporter, her daily jobs include inspecting the nearly 15,000-sqm farmland on the roof of Futian Agricultural Products Wholesale Market, introducing eco-farming to visitors, carrying out plans to plant seasonal vegetables and fruits and serving customers who rent land and order home-delivered vegetables.

    “The project started in 2012 when both the local government and my company heard about the need to develop urban rooftop farming,” she said. “Embracing the call for organic vegetables, we rented the area and consulted experts on building our slow-growth farm and became the only CBD roof-farming lab in Shenzhen.”

    The urban farmer said they gradually built the land with a specially designed irrigation system, a drainage system, mixed soil and insect-catching devices.

    “It is actually complicated to start a rooftop farm,” she said. “You need to consider various problems. For instance, you need to calculate the weight of the soil and bricks and the water the soil may absorb. Then you need to consult your building’s developer on whether the roof can support that kind of weight to make sure it won’t collapse.

    “Also, you need to design a drainage plan. You have to know where the water goes to and how it can irrigate your garden,” she said. “To prevent water loss, you can put a waterproof layer on the roof first.”

    She also said it’s important to decide how thick the soil layer should be and what should be included in the soil. She said her company has built a team to research the best soil for roof farming. “We mixed the soil to make sure it was fertile. The soil may lose its nutrients as more plants grow in it,” she added.

    To maintain the quality of the soil, they pour enzyme infused water into it from time to time.

    “We make our own enzymes,” she explained. “The workers collect the rotten leaves and fruit and put them into a big container. Then we let them ferment. After a while we will add the fermented water to the soil.”

    She said the best way to make the soil fertile without the help of a chemical fertilizer is to use homemade enzymes rather than simply burying the rotten leaves in the soil because the leaves will be a hotbed for various bacteria and insects, which could harm the garden. The fermentation process will kill most insects and bad bacteria.

    To kill pests, her team uses a special device that attracts them into a trap using the insects’ favorite odors.

    But above all, He said an eco-friendly farmer needs to expect imperfections.

    “Growing plants requires time and strength. Sometimes the plants turn out ugly, but they will be better than those that grow in bad, artificial environments,” she said.

    1 First, check with your property owner and/or the building code. Questions about accessibility, building height restrictions and fire regulations can prohibit rooftop gardening. You also need to discuss it with other residents in your apartment building.

    2Make sure the roof can hold the load. Get a licensed pro to check this. Soil and pots are heavy to begin with and will get heavier as the plants grow.

    3Learn from experienced rooftop gardeners, or join an online group to discuss details.

    4Does your roof get too much shade from nearby buildings or the terrace above? Too much sun can also be a problem if your plants swelter on a concrete roof.

    5Besides the sun beating down on the roof, there is ambient heat being reflected from the roof surface, surrounding buildings, cars and metal exhaust and utility structures. You will probably want to provide some sort of shade.

    6Wind can whip down urban streets, especially on high rises. You may want to consider some type of wall or fencing.

    7Electricity isn’t essential, but it sure makes things easier. If you are planning on enjoying your garden at night, candles are the best lighting for weeding.

    8You also have to think about how much you are willing to spend. You can start small and add on, buying more pots and plants (and soil) as you go.