Six ways to do it
How do you bring roots water, food, and air?
Growers have many ways to do it. Here are six common ones.
Six ways? Let's look inside each one.
Think of ways to give a thirsty friend a drink. You could hand them a straw, a full glass, or a slow drip.
Each system is a different way to bring water to roots.
A strip of cloth soaks up water, like a paper towel dipped in juice. The water climbs the cloth into the pot.
This is a wick systemA way to grow where a strip of cloth soaks up water and carries it to the roots. No pump.
See it in the glossary, and it needs no pump.
- A · wick
- B · growing mix
- C · water with plant food
Fill a tub once and set a plant on top. As it drinks, the water drops, and the top roots get air.
This no-pump way is the Kratky methodA way to grow where you fill a tub once. As the water drops, the top roots get air.
See it in the glossary.
- A · net pot
- B · air gap
- C · roots in the water
Here the roots hang in deep water all the time. A pump blows in bubbles so the roots get air.
This is deep water cultureA way to grow where roots hang in deep water, and a pump blows in bubbles.
See it in the glossary.
- A · net pot
- B · water with plant food
- C · air stone
- D · air pump
Plants sit in holes along a sloped channel. A pump sends a thin stream of water down it, over the roots.
A thin layer like this is a film, so this is nutrient filmA way to grow where a thin stream of water runs down a sloped channel over the roots.
See it in the glossary.
- A · channel
- B · thin film of water
- C · pump
- D · return pipe
A timer turns on a pump, and water floods a tray of plants. Then the pump stops, and the water drains back.
Like a tide going in and out, this is ebb and flowA way to grow where a pump floods a tray of plants, then the water drains back.
See it in the glossary.
- A · flood tray
- B · overflow pipe
- C · pump
- D · timer
A pump pushes water through a thin tube above the plants. Drops fall onto each pot, and extra water drains away.
This is a drip systemA way to grow where a pump sends water through thin tubes, and drops fall onto each plant.
See it in the glossary.
- A · drip line
- B · dripper
- C · pump
- D · drain pipe
Your turn. Match each system to its picture.
Look for clues: a cloth wick, bubbles, a tray, a channel, or drops.
Match each name to a letter.
Tap a letter, then tap its name.
Which name goes with A?
Match each name to a letter.
The answer:
- A · ebb and flow The tray floods, then drains back down.
- B · wick system A cloth wick carries water up, with no pump.
- C · nutrient film A thin stream runs down a sloped channel.
- D · Kratky method The water sits low, and there is no pump.
- E · drip system A thin tube drips water onto each pot.
- F · deep water culture Roots hang in deep water full of bubbles.
Check 1 of 3
In which system does the water drop, so the top roots hang in air?
Show the answer
The Kratky method. Right. As the plant drinks, the water drops and leaves an air gap.
Check 2 of 3
Which system floods a tray, then lets it drain?
Show the answer
Ebb and flow. Right. A timer turns the pump on and off, like a tide.
Check 3 of 3
Why does a deep water culture tub need an air pump?
Show the answer
The roots stay under water and still need air. Right. The bubbles carry air to the roots.
You just learned six ways to bring water to roots.
Next up: The nutrient solution.
Go deeper: picking a systemOpenClose
Wick and Kratky systems are passive, which means no pump moves the water. They need no electricity and cost little to set up.
A Kratky tub gets all its water and plant food at the start. It works best for quick, leafy crops such as lettuce.
The Kratky method is named after B. A. Kratky, a plant scientist at the University of Hawaii who studied and described it.
Nutrient film channels slope gently so the thin film of water keeps flowing. If the pump stops, the roots can dry out and the plants wilt quickly.
Ebb and flow is also called flood and drain. Each time the tray drains, the roots are left in air and can take in oxygen.
Some drip systems send extra water back to the reservoir to use again. Others let it drain away and never reuse it. These are called open systems.
Some growers float plants in foam rafts on long tanks of nutrient solution.
There are other systems too. In aeroponics, roots hang in a closed box and get sprayed with a mist of nutrient solution.
Sources
- Dunn, B. Hydroponics. Fact sheet HLA-6442. Oklahoma State University Extension, 2025. Link
- Hart, C. Home Hydroponics (handouts). University of Illinois Extension. Link
- Johnson, K. Growing without soil: Getting started with hydroponics at home. Good Growing blog, University of Illinois Extension, 2026. Link
- Kratky, B. A. Three non-circulating hydroponic methods for growing lettuce. Acta Horticulturae 843: 65-72, 2009. Copy hosted by the University of Hawaii CTAHR. Link
- Eason, H. 'Set It and Forget It' Hydroponic Lettuce. HS1488. UF/IFAS Extension. Link
- Nelson, M., G. Langellotto, and L. Nackley. Hydro Hints: Deep Water Culture. EM 9455. Oregon State University Extension Service, 2025. Link
- Nelson, M., II, G. Langellotto, and L. Nackley. Hydro hints: Nutrient film technique. EM 9457. Oregon State University Extension Service, 2025. Link
- Nelson, M., II, G. Langellotto, and L. Nackley. Hydro hints: Ebb and flow. EM 9458. Oregon State University Extension Service, 2025. Link
- Hochmuth, G. J. Production Systems. Florida Greenhouse Vegetable Production Handbook, Vol 2. CV255. UF/IFAS Extension. Link
- Grow Easy. College of Tropical Agriculture and Human Resources, University of Hawaii, 2019. Link