Chapter Notes: Hydroponics: Growing Plants without Soil

Table of Contents
1. Introduction
2. What is Hydroponics?
3. Why Hydroponics is Needed?
4. What Will I Need? (Materials & Equipment)
5. Safety Precautions
6. Conditions Needed for Plant Growth
7. Hydroponic Methods
8. Compost Tea (Liquid Manure)
9. Maintaining Water pH
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Introduction

As the population of the world is increasing, the need for food is also rising. Farmers face many challenges like shortage of fertile land, soil degradation, and deforestation. To overcome these problems, scientists are finding new methods of farming which can give healthy food in an eco-friendly way. Hydroponics is one such method where plants are grown without soil. Instead, their roots are placed in water mixed with nutrients. This method allows precise control over plant growth and helps in producing more crops in less space.

What is Hydroponics?

The word "Hydroponics" comes from Greek:

• Hydro = water
• Ponos = labour or work
• It is a farming method where plants grow in nutrient-rich water instead of soil.
• Farmers can give exact nutrients needed by plants.
• It is also called precision farming technique.
• Hydroponics supports:
  • Multistorey (vertical) farming.
  • Reuse of water and fertilisers.
  • Control of temperature, humidity, and light.
  • Urban farming in cities using less space.

Why Hydroponics is Needed?

• Increasing demand for food due to growing population.
• Forest land is cut for farming → Deforestation and climate change.
• Continuous use of soil leads to nutrient loss and soil degradation.
• Excess use of fertilisers damages soil further.
• Water pollution, mining, and over-irrigation also reduce soil quality.
• In India, about 33% of total land area is degraded. Nearly 109 million hectares of land has poor soil quality.
• To solve these problems, Government of India promotes hydroponics and aeroponics under Mission for Integrated Development of Horticulture.
• Aim → Sustainable farming (healthy food with minimum harm to environment).

What Will I Be Able to Do?

By learning hydroponics, you will be able to:

• Grow microgreens using simple hydroponics.
• Build hydroponic units with methods like Wick system, Deep Water Culture (DWC), and Nutrient Film Technique (NFT).
• Prepare organic liquid manure (compost tea).
• Maintain water quality by adjusting pH.

What Will I Need? (Materials & Equipment)

Different hydroponic methods require different things:

General tools:

• Scissors, paper knife, gloves
• Seeds or seedlings
• Coco peat, sawdust, or soil
• Used PET bottles (2L), food containers, or buckets (15-20L)
• Cotton thread/cloth strip (wick)
• Net pots (50mm), Styrofoam sheets (10mm)
• PVC pipes (76mm, 1m long), hand drill, silicon glue, heat gun
• Submersible pump (18W) with hosepipe
• Aerator (2.5W) with diffuser

For Compost Tea:

• Compost/vermicompost (100g)
• Muslin cloth (1m)
• Jaggery (50g)
• Water bucket (15L)

For Water pH Adjustment:

• pH paper and pH scale
• Citric acid, vinegar, bottle

Safety Precautions

Using tools and machines:

• Always wear gloves.
• Handle sharp tools and electric machines (drill, submersible pump) carefully.
• Pay attention to teacher's demonstration.

Using electrical gadgets:

• Be cautious with aerators and pumps.
• Work under teacher's guidance.

Internet safety:

• Take teacher's help while using Internet.
• Never share personal details online.

Conditions Needed for Plant Growth

Plants need air, sunlight, temperature, humidity, carbon dioxide, nutrients, soil and water.
Hydroponics can replace soil and still provide all needs:

• Germination of seeds: Done by soaking in water.
• Support to plants: Roots fixed in net pots or floating sheets.
• Sunlight: Natural sunlight or artificial lights (LED, tubelight).
• Nutrients: Directly mixed in water.
• Growth medium: Instead of soil, use coco coir, coco peat, gravel, sand, clay, pebbles, rockwool, vermicompost.
• Microbes: Added in water to help plants absorb nutrients, fight diseases, and grow better.

Hydroponic Methods

1. Wick Method

• Made using PET bottles (cut and inverted).
• A cotton wick pulls water upward to soil by capillary action.
• Simple, no electricity needed.
• Maintenance → only refill water, check wick, remove old plants.

2. Deep Water Culture (DWC) / Bucket Method

• Roots suspended in water containing nutrients.
• Uses Styrofoam sheets or net pots to hold plants.
• Requires aerator to supply oxygen to roots.
• Healthy roots are white; brown roots mean oxygen deficiency.
• Must prevent algae by covering water surface.

3. Nutrient Film Technique (NFT)

• Roots stand in a shallow stream of nutrient water flowing in PVC pipes.
• No aerator needed as moving water provides oxygen.
• Uses less water and more plants can be grown vertically.
• Maintenance → adjust slope and water level to prevent overflow or drying.

Compost Tea (Liquid Manure)

• Needed because hydroponics does not use solid compost.
• Made by brewing compost/vermicompost in water with jaggery for 2-3 days using aerator.
• Gives dark brown liquid manure rich in nutrients.
• Add 1L compost tea to 10L hydroponic water.
• If smell is bad → poor aeration or excess compost.

Maintaining Water pH

• Ideal pH = 6.0 to 7.0.
• If pH > 7 (alkaline) → add weak acids like vinegar or citric acid.
• If too acidic → add a base to bring pH back to 6.5-7.
• Proper pH ensures nutrient absorption and healthy growth.
• Strong acids (phosphoric, sulfuric, nitric) → need small quantity but unsafe.
• Weak acids (citric, vinegar, monoammonium phosphate) → safe for handling.