Brief description

Hydroponics is a method of growing plants without soil by delivering water, oxygen, and dissolved nutrients directly to the roots. It enables crop production where soils are poor, contaminated, or scarce.

Use / Function

• Food production: Grow vegetables and herbs in controlled conditions.
• Water efficiency: Reuse and recirculate water with minimal losses.
• Space efficiency: Produce in small areas, indoors, or on rooftops.
• Soil independence: Avoid soil-borne pests, weeds, and salinity.

Operating principle

Plants need water, oxygen, light, and nutrients. Hydroponics replaces soil with an inert medium or bare roots while a nutrient solution provides minerals. Oxygen reaches roots through air gaps, flowing water, or porous media.

How to create it

1. Choose a simple system: A wick system or static reservoir (Kratky) requires no electricity.
2. Build a reservoir: Use a sealed container to hold nutrient water.
3. Support the plant: Fill a net cup or perforated pot with gravel, sand, or clay and place the seedling.
4. Deliver nutrients: Mix clean water with dissolved nutrients and keep the roots partially submerged.
5. Provide oxygen: Leave an air gap, stir daily, or circulate water using a pump.
6. Manage light and heat: Provide consistent light and protect the system from overheating and algae.

Materials needed

• Essential: Clean water, containers, inert media (gravel, sand, or clay), and seeds.
• Structure: Wood frames or glass covers for protection and humidity control.
• Filtration: charcoal to reduce odors and organic buildup when water is reused.
• Possible substitutes: Fiber wicks made from plant fibers and gravity-fed flow from elevated reservoirs.

Variants and improvements

• Wick system: Capillary action feeds roots from below with no moving parts.
• Kratky method: Static nutrient solution with a growing air gap.
• Deep water culture: Roots sit in aerated water for fast growth.
• Nutrient film technique (NFT): Thin flowing layer of nutrient water over roots.
• Ebb and flow: Periodic flooding and draining to oxygenate roots.

Limits and risks

• Nutrient imbalance: Incorrect mix leads to stunted growth or leaf burn.
• Root oxygen loss: Stagnant water can cause rot and disease.
• Algae growth: Light-exposed water encourages algae and clogs.
• Temperature swings: Warm water lowers oxygen and increases pathogens.
• Dependency: If circulation stops, sensitive crops decline quickly.