What Is Hydroponics? In a Singapore Context

Hydroponics is a way of growing plants without soil, feeding their roots with water that carries the nutrients they need. It sounds high-tech, but the basic idea is simple: give a plant the same things soil provides, just deliver them more directly.

This guide explains how hydroponics works, the main systems used, what grows well in them, and why the method suits a land-scarce city like Singapore. It's written for students and teachers, but anyone curious about soil-free growing will find it useful. It's part of our series on urban farming, alongside our guide to vertical farming.

What Is Hydroponics?

Soil does three jobs for a plant: it holds water, stores nutrients, and anchors the roots. Hydroponics replaces all three. The nutrients are dissolved into water, the water is delivered straight to the roots, and a small amount of growing medium (or the structure of the system itself) holds the plant upright.

Because the roots sit in a measured solution rather than searching through soil, the plant spends less energy growing roots and more on leaves and stems. That's a large part of why hydroponic crops often grow faster than the same plant in the ground.

What Plants Need to Grow Without Soil

Take soil out of the picture and you have to supply everything a plant would normally draw from it:

• Water: the base of the whole system, carrying everything else to the roots.
• Nutrients: mainly nitrogen, phosphorus and potassium, plus smaller amounts of minerals like calcium, magnesium and iron.
• Oxygen: roots need to breathe, so the water is aerated or kept moving to stop them drowning.
• Light: from the sun outdoors, or LED grow lights indoors, to power photosynthesis.
• Support: a net pot, a cube of growing medium, or the channel itself to hold the plant in place.

Growers also watch the water's pH, keeping it slightly acidic at around 5.5 to 6.5 so the roots can absorb nutrients properly. It's one of the easiest things for a class to measure and track.

Common Types of Hydroponic Systems

Several setups all count as hydroponics. These are the ones you'll come across most often:

1. Deep water culture (DWC): roots hang in a tank of aerated nutrient water. Simple and cheap, which makes it a common first project.
2. Nutrient film technique (NFT): a thin stream of nutrient water runs along a sloped channel, flowing past the roots and back to a reservoir. Widely used for leafy greens.
3. Ebb and flow: a tray is flooded with nutrient water on a timer, then drained. The cycle feeds the roots and lets them take in oxygen between floods.
4. Drip systems: nutrient water drips onto each plant's base, with any excess collected and reused.
5. Aeroponics: a close relative, where roots hang in air and are misted with nutrient solution rather than sitting in water.

What Grows Well in Hydroponics

Fast, leafy crops are the sweet spot. Lettuce, kai lan, bok choy, spinach and herbs like basil and mint all do well, and microgreens are ready in as little as 7 to 21 days. Heavy or deep-rooted crops such as potatoes and carrots are harder to grow this way, and large fruiting plants like watermelon need more support and space than most systems offer. That's why commercial city farms, including those in Singapore, tend to focus on greens and herbs.

Why Hydroponics Suits Singapore

Singapore farms only 0.8% of its land and imports over 90% of its food, so any method that grows more in less space is valuable. Hydroponics stacks neatly into vertical racks and indoor rooms, and because most systems recirculate their water in a closed loop, they can use up to 90% less than soil farming. Citiponics, which runs a rooftop farm on an Ang Mo Kio carpark, says it uses roughly 1% of the water a soil farm would need.

Grown indoors, the crops are shielded from pests, so there's no need for pesticides, and harvests keep coming through the year regardless of the weather. The trade-off is energy: indoor systems run on lights and cooling, so their environmental benefit depends on how that electricity is produced.

Hydroponics in the Classroom

A small hydroponic setup is one of the clearest science lessons going. Students can see the roots they'd normally never look at, measure pH and adjust it, track growth day by day, and test how changing light or nutrients affects a plant. Set up two systems with one variable different between them and you have a ready-made experiment.

At GreenLoopFarms, school groups see these systems running at full scale and take part in the growing process first-hand.

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Frequently Asked Questions About Hydroponics

How does hydroponics work without soil?

Soil normally holds water, stores nutrients and supports the plant. Hydroponics does all three another way: nutrients are dissolved in water, the water is delivered to the roots, and a net pot or growing medium holds the plant upright.

Is hydroponic produce healthy?

Yes. Hydroponic greens contain the same nutrients as soil-grown ones, and because city farms can harvest and sell them the same day, they often reach you fresher, before their vitamins have broken down in transit.

Does hydroponics really save water?

It does. Most systems recirculate their water rather than letting it drain away, so they can use up to 90% less than conventional soil farming that loses water to evaporation and runoff.

What plants grow best in hydroponics?

Leafy greens and herbs such as lettuce, bok choy, kai lan, basil and mint, along with microgreens. Deep-rooted vegetables like carrots and potatoes, and large fruiting plants, are more difficult.

Can I set up hydroponics at home or in school?

Yes. A simple deep water culture system, with a container, an air pump and a few net pots, is inexpensive and a good starting point for growing herbs or running a classroom experiment.

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See Hydroponics in Action

Reading about a system only goes so far. Visit a working indoor farm in Singapore to see hydroponics at scale, or taste the results for yourself.

Book a Farm Tour Shop Microgreens

 

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Sources & Data Citations

• Closed-loop hydroponic systems can use up to 90% less water than conventional soil farming, which loses water to evaporation and runoff. (Industry and agricultural research)
• Citiponics grows pesticide-free leafy greens on an Ang Mo Kio carpark rooftop and reports using around 1% of the water a soil farm would need. (Vulcan Post)
• Arable land accounts for 0.8% of Singapore's total land area, and the country imports over 90% of its food. (World Bank; Singapore Food Agency)