After a trip to an organic farm in Taiwan, where they saw farmers grow food without pesticides and tasted the fresh greens grown there, this couple planned to cultivate vegetables the same way in Singapore.

So Ms Chia Ei Ei, 40, a teacher, and her husband Kevin Chua, 43, an allied educator, rented a rack from Pocket Greens, an urban farm in Bukit Panjang.

Under the vertical rack adoption programme, one can rent a rack measuring 1.8 by 1m at $50 a month to grow vegetables. The minimum lease is three months.

The farm started the programme in 2014 in collaboration with the Northwest Community Development Council. Forty per cent of the proceeds go to needy students in the district.

Growing vegetables on a rack is like having an efficient multi- storey farm. Each rack comes with four shelves and each shelf can hold five trays, which measure 56 by 23cm each.

On these trays, you spread out a layer of specially mixed compost, sow the seeds and then come back a week or two later to harvest. An automated watering system saves gardeners the hassle of coming back every day.

Vegetables that can be grown on racks include microgreens - tiny young greens which are harvested when they are still juvenile plants. They include pea shoot, beet, broccoli and kale.

Different species take different times to mature. Among the fastest are radish and sunflowers, which can be harvested in five days, while a slower growing plant such as kai lan or lettuce will take 14 days.

Ms Chia and her husband have been taking their nine-year-old daughter, Megan, to the farm. She says: "It has given Megan, who dreams of becoming a farmer, a glimpse of what farming is like."

The family grows microgreens such as sunflower and broccoli sprouts, xiao bai cai and red radish, and adds them to salads.

Ms Chia says: "Compared with buying from the market, I am assured that there is no pesticide used. There is also a sense of fulfilment from growing our own veggies."