Project 1: Hydroponics: Growing Plants without Soil – Class 8 Vocational Education Chapter 1 Notes & NCERT PDF

About the Project

Hydroponics is a way of growing plants without soil (or with very little soil). The word comes from two Greek words: 'hydro' = water and 'ponos' = labour or toil. Plants grow in a nutrient-rich water solution, so they get exactly the nutrients they need. That is why hydroponics is also called a 'precision farming technique'.

Why do we need it? The book explains the problem clearly:

The Government of India promotes hydroponics and aeroponics through the Mission for Integrated Development of Horticulture (Ministry of Agriculture and Farmers Welfare). Hydroponics also allows multistorey (vertical) farming, reuse of water and fertiliser, control of temperature, humidity and light (for example inside a polyhouse), and urban farming in cities.

Did you know? ISRO sprouted cowpea seeds in its PSLV-C60 POEM-4 mission — a step towards 'space gardens'.

What You Will Learn

Materials & Tools

Step-by-Step Activities

Activity 1: Field visit

Visit a hydroponic unit, a home gardener, a Krishi Vigyan Kendra (KVK), an agricultural university or research centre. Note new technologies (liquid nutrients, artificial lights, control of water supply) and ask experts about advantages, disadvantages and harvesting methods.

Activity 2: Growing microgreens

Microgreens are young seedlings of vegetables and herbs, harvested after the first 2–4 leaves appear (1–3 inches). They are rich in vitamins C, E, K and A, and carotenoids, and can be grown from cabbage, beetroot, fenugreek, mustard, spinach, coriander and wheat.

Sprouts vs microgreens: sprouts grow without light and are eaten with roots in 2–5 days; microgreens grow with light and are eaten without roots in 10–15 days.

Activity 3: Wick method

Cut the top 10–15 cm off a 2 L PET bottle, flip it into the bottom part, pass a cotton wick through a hole in the cap, fill the reservoir with water and the top with growth medium, then plant. Water rises up the wick by capillary action. The wick method needs little maintenance because it has no pump or aerator.

Activity 4: Deep Water Culture (Bucket method)

Plant roots hang in nutrient water; plants sit in net pots held by a lid or Styrofoam float. Use a 10–15 L bucket, make holes in the lid for net pots (5–10 cm apart), fill with cocopeat and 2–3 spinach seeds or seedlings, keep water just touching the base of the pots, and add an aerator. Aeration supplies Dissolved Oxygen (DO) — healthy roots are white; brown roots may lack oxygen. Covering the water blocks sunlight and prevents algae.

Activity 5: Nutrient Film Technique (NFT)

Plants stand in a thin film of flowing water, so NFT needs no air pump. Use a 1 m PVC pipe (76 mm) with end caps and holes for 6–7 plants; stack 4–5 pipes on a frame; a pump sends water from a reservoir, and an on–off timer can control it. Keep the water at about half the pipe diameter and adjust the slope to avoid overflow. NFT uses vertical space and less water than DWC. The ICAR AI-DISC app helps identify plant diseases, pests and deficiencies.

Activity 6: Making compost tea

Put 100–150 g compost in muslin cloth in a 15 L bucket with about 10 L water, add 50 g jaggery or sugar (food for microbes) and aerate for 2–3 days. Use 1 L compost tea per 10 L of hydroponic water. Good compost tea is dark brown and smells earthy; if too dark, dilute 1:3; a bad smell suggests poor aeration or too much compost.

Activity 7: Maintaining water pH

Nutrients move best when water pH is 6.0 to 7.0; the target is 6.5–7.0. If pH is above 7 (alkaline), add a weak acid such as vinegar (acetic acid) or citric acid (lime juice); if too acidic, add a base. In the experiment, 20–30 mL of weak acid is added to 1 L of tap water to bring it to pH 4, and its effect on plants is observed in 2–3 days.

Safety First

Key Terms

Think and Answer (Hints)

Career & Community Connections

KVKs, ICAR institutes and agricultural universities train farmers in hydroponics. India also has traditional floating farms — the Dal Lake floating gardens (Srinagar), Phumdis of Loktak Lake (Manipur) and floating gardens of coastal Odisha — linked in spirit to hydroponics.

Common Mistakes