Six ways to do it

Students will

• Name six common hydroponic systems.
• Describe how each system brings water, food, and air to the roots.
• Tell which systems use a pump and which do not.

New words

wick-system

A way to grow where a strip of cloth soaks up water and carries it to the roots. No pump.

kratky

A way to grow where you fill a tub once. As the water drops, the top roots get air.

deep-water-culture

A way to grow where roots hang in deep water, and a pump blows in bubbles.

nutrient-film

A way to grow where a thin stream of water runs down a sloped channel over the roots.

ebb-and-flow

A way to grow where a pump floods a tray of plants, then the water drains back.

drip-system

A way to grow where a pump sends water through thin tubes, and drops fall onto each plant.

Talk about it

Which system would you pick for a classroom windowsill, and why?

Check questions and answers

1. In which system does the water drop, so the top roots hang in air?

   • The Kratky method (answer) Right. As the plant drinks, the water drops and leaves an air gap.
   • Ebb and flow Not quite. That one floods a tray with a pump, then drains it.
   • Deep water culture Not quite. That one keeps the water deep and adds bubbles.

2. Which system floods a tray, then lets it drain?

   • Ebb and flow (answer) Right. A timer turns the pump on and off, like a tide.
   • A drip system Not quite. A drip system drops water onto each pot.
   • A wick system Not quite. A wick system has no pump to flood anything.

3. Why does a deep water culture tub need an air pump?

   • The roots stay under water and still need air (answer) Right. The bubbles carry air to the roots.
   • To push water up to the leaves Not quite. The roots already sit in the water.
   • To keep bugs away Not quite. Think about what roots need besides water and food.