No water? No worries: A hydroponics project in Abu Dhabi

We meet a family in Abu Dhabi who have transformed their swimming pool into a full-scale hydroponics system.

The hydroponics system in the empty swimming pool at the Hartanto family’s villa in Khalifa City, Abu Dhabi. The whole family has been involved, including their three young children. Courtesy Nifti anShow more

An Indonesian family living in Abu Dhabi dipped their toes into the world of hydroponics after they decided to drain the swimming pool of their Khalifa City villa and create a vertical garden in its place.

The Hartantos’ daughter is still young, so a pool just outside the kitchen door wasn’t an ideal feature for safety reasons – but once empty, the depth of the former swimming pool provided the perfect framework for a hydroponics project. The idea was sparked after Nifti Hartanto visited her sister’s garden in Malaysia and saw the vegetables she was growing there.

Hydroponics is a method of growing plants without soil, nourishing them instead with mineral-­nutrient solutions carried in water. It provides a space-saving, cost-efficient system of cultivating edibles that’s ideal for the UAE – it consumes less water than conventional growing. In addition, it bypasses local soil, which is often lacking in organic matter and minerals.

The Hartantos’ hydroponics undertaking has involved Nifti’s entire family: her husband, Rudi, their sons Muhammad Rizgi, 11, and Maulana Ibrahim, 9, and daughter Nashhah Tagiyyah, 5. The garden currently has a capacity of 150 plants, where tomatoes, cabbages, chillies, lettuces, aubergines and broccoli are grown, and shared with neighbours and friends.

Rudi, a geological engineer, says that the set-up is “very simple; everyone can do it”, and can be achieved at relatively little expense during the course of a weekend. The equipment needed is readily available at nurseries, hardware stores and pet shops, and the family manages all care and maintenance of the project.

It has also provided an opportunity to educate the Hartantos’ children about the cultivation of food, from seed to plate. They’re visibly enthusiastic about what grows here – and extremely discerning about the flavour of the produce.

The hydroponic garden has become something of a community hub, with neighbours getting to share the fruits (and vegetables) of the family’s labours. They have even been called in to conduct taste tests, comparing the produce to local supermarket purchases. The hydroponics harvest won hands down.

The system consists of plastic drainpipes (sourced from any hardware store), into which a series of evenly spaced holes are drilled on one side. Investing in a hole-saw set (an attachment for your drill) is essential for this task. The size of the holes should support the insertion of plastic plant pots. Rudi advises that a better grade of drainpipe offers greater longevity – don’t buy the cheapest, flimsiest pipes, because this could prove a false economy.

A large plastic bucket with a lid acts as a reservoir for the system, into which the hydroponic nutrients are added at a ratio of 5 millilitres of nutrient to 1 litre of water (although concentrations between products can vary). Rudi estimates that the sealed system uses about 60 litres of water (what an average lawn might consume in just a few days). There’s relatively little evaporation, so it’s very energy efficient, with water needing to be topped up every couple of weeks, when additional nutrients are added into the mix at the same ratios.

It’s not necessary for the hydroponic garden to be plumbed directly into mains water, because the bucket/reservoir holds all necessary hydration, but it’s helpful to have this in range of a standing water supply.

A small pump is installed to take the water from the tank around the hydroponic system. These can be found at any pet shop dealing with fish tanks (for about Dh130) and should be able to work to a height of one metre to 1.2 metres, circulating the solution to the uppermost meeting point for the circuit. A larger, stronger pump isn’t necessarily better, because the water will be pushed around the system too quickly. You’re aiming for a gentle flow, which will be kept running 24/7.

Gravity does the rest: each pipe is angled gently downwards and held in place by a series of mini ropes threaded through hooks attached to the walls, which can be adjusted to get the angles right. These offer the added benefit of supporting the system once the plants become established and are large and heavy.

Maintenance consists of checking the holding tank’s water level to ensure that the pump is submerged and able to do its work (it will burn out if it has nothing to pump), plus topping up the nutrient levels of the water to replace what the plants consume.

Once growing is underway, the roots of the pots can be gently trimmed if necessary, to prevent big, thick root balls blocking the drainage pipes and disrupting an even water flow.

For the plant containers themselves, the family purchased robust plastic cups from a supermarket, into which hydration/feeding holes were made – Rudi prefers a heated soldering iron for the job, but a drill also works.

This system of hydroponics almost entirely does away with the need for soil, so grow rocks, commercially known as Hydroton, are used. These are made from kiln-fired lightweight clay, formed into pebbles that provide a water-permeable anchor from which the plants can grow. The nutrients ordinarily found in soil will flow around these as the water is pumped through the system, and the plants will draw what they need for nourishment.

Soil is briefly used in the early stages of growth, however, because the family cultivates everything from seed. Plants begin life in shallow seed trays laid outside. Once the seedlings have four leaves, they’re ready for transfer. Nifti gently washes the root and transplants the seedlings into pots fitted with Hydroton balls. Removing the soil helps to keep the system functioning cleanly and avoids clogging the filters.

Netting has been erected over some of the crops to discourage birds, but there tends to be fewer pests with hydroponic systems because soil-borne creatures that attack root systems are removed from the picture. Nonetheless, to discourage aphids and caterpillars, Nifti mixes a solution of ­water and bicarbonate of soda, and sprays this on the leaves of her plants.

Hydroponic solutions can be ordered online, but when the family first started growing they found it difficult to source what they needed locally. Not to be dissuaded, Rudi brought in the white powdered mix directly from Malaysia (and in so doing attracted the attention of vigilant UAE customs officers, who tested each box before allowing him through).

Hydroponic mixtures will generally contain the following macronutrients: hydrogen, nitrogen, phosphorus, potassium, magnesium and calcium, as well as other trace elements. If the solution is too weak, plants will display yellowing leaves and lack growth; if the nutrient level is too high, leaves may curl or burn – so follow the instructions given with the product you buy.

Rudi says that if his system was located indoors, there’s no reason why plants couldn’t grow year-round. Large-scale commercial hydroponic operations in this region are already doing just that, using 100,000 litres of water in a single operation. Whatever the scale, there’s no denying that this is an efficient way of growing your greens.

Recipe

Too many tomatoes at harvest time? Try Nifty Hartanto’s spicy Indonesian sambal recipe:

Ingredients:

• 5 red chillies

• 3 shallots

• 5 cherry tomatoes or ½ large tomato, cut into small pieces

• 2 tbsp oil

• 1 pinch of salt, to taste

• 1 pinch of sugar, to taste

• 1/4 lime, juiced

• 1/2 tsp shrimp paste (optional)

Directions:

1. Pound the chillies, shallots, garlic, shrimp paste and tomato with a mortar and pestle until they form a fine paste.

2. Heat a little oil in a frying pan and sauté the paste, stirring until fragrant.

3. Remove from heat and season with salt, sugar and lime juice.