Include NCERT Class 8 Kaushal Bodh Solutions and Class 8 Vocational Education Chapter 1 Hydroponics Growing Plants without Soil Notes in your preparation plan to revise efficiently.
Hydroponics Growing Plants without Soil Class 8 Notes
Challenges in Agriculture and the Need for Sustainable Farming
- Growing world population increases the demand for food, which requires more farmland and often leads to deforestation.
- Repeated use of the same land causes soil degradation, meaning the soil loses its natural nutrients over time.
- Excessive use of chemical fertilisers further reduces soil quality.
- Wind and rain erosion, industrial pollution and mining also damage the soil.
- In India, about 33% of land (around 109 million hectares) is affected by degradation and is losing its quality.
- Sustainable farming is needed to produce healthy food while minimising negative impacts on the environment. Hydroponics is an example of sustainable farming.
Meaning of Hydroponics
- The word hydroponics comes from two Greek words, hydro (water) and ponos (labour or toil).
- Hydroponics is a way of growing plants in a nutrient-rich water solution instead of using soil.
- Crops grown in cities using this method are known as urban farming practices.
Benefits of Hydroponics
- In hydroponics, plants receive nutrients dissolved in water. This allows farmers to control the exact amount given, making it a form of precision farming.
- Water and fertilisers can be recirculated and reused, which significantly reduces waste.
- Vertical (multi-layer) farming makes it possible to produce more food in much less space because soil is not required.
- A controlled environment using a polyhouse helps regulate temperature, humidity and light for optimal growth.
Government Initiative
- The Government of India promotes hydroponics under the Mission for Integrated Development of Horticulture, Ministry of Agriculture and Farmers Welfare.
- Technologies like hydroponics and aeroponics (where plants are not in direct contact with soil) are promoted under this mission.
Microgreens Setups
Wick Hydroponic Setup
NFT Hydroponic Setup
DWC Hydroponic Setup
Compost Tea Setup
Materials Required for Adjusting the ph
How to Stay Safe?
- Wear gloves while handling all tools and materials.
- Pay attention during demonstrations before using any tool.
- Take special care when using sharp tools and power-driven machines like a drill machine and submersible pump.
- Work with electrical gadgets like aerators and submersible pumps only under the supervision of a teacher or expert.
- Indian Space Research Organisation (ISRO) successfully grew cowpea seeds in space during the PSLV-C60 POEM-4 mission.
- This ‘space garden’ experiment is a vital step toward growing fresh food for future space stations and human colonies.
What You Need to Know Before Start?
- Plants need air, temperature, humidity, carbon dioxide, nutrients, soil and water to grow.
- Plants also need help from microbes to grow well.
- Microbes are very tiny living organisms that cannot be seen without a microscope.
- They break down complex organic matter into simpler substances so that plant roots can absorb nutrients easily. Some microbes protect plants from diseases.
- They can also help plants communicate with nearby plants.
- In hydroponics, care must be taken to add only beneficial microbes to the water.
- In hydroponics, fulling these needs even without soil, is explained in table below
Conditions for Plant Growth and How They Can be Fulfilled
| Conditions tor Plant Growth | How are They Fulfilled in Soil? | Can. We Replace Soil? |
| Germination of seeds | Seeds absorb water and start germination. | Yes, seeds can be soaked in water to germinate, just like sprouts. |
| Physical support for plants | Roots hold soil to provide support to plants. | In hydroponics, plants are placed on floating sheets or net pots. |
| Sunlight for growth | Plants absorb sunlight for photosynthesis. | Both natural sunlight and artificial light (LED/tubelight) are used. |
| Nutrients for plant growth | Plant roots absorb minerals from the soil. | Minerals are added to water in the required quantity for roots to absorb. |
| Any other specific need | Crops are sown directly in soil with compost or fertilisers. | Growth media like coco peat, gravel, sand, and clay pebbles are used instead. |
Internet Tip —Search using these keywords
- Basics of hydroponics + school student
- (DIY) hydroponics + instructions + home
- Hydroponic system + beginner
- Try to find videos created by Indian Council of Agricultural Research (ICAR) or Agrii
Growing Plants using Hydroponics
- You have to grow microgreens, vegetables and flowering plants using the hydroponic technique.
- Plants need time to grow, so proper planning of activities is necessary.
- Planning helps in harvesting the plants at the right time.
- Use the table for using different methods of hydroponic techniques.
- Dal Lake in Srinagar, Jammu and Kashmir has floating farms.
- ‘Phumdis’ in Loktak Lake of Manipur are floating masses used for farming.
- Floating gardens are also found in the coastal areas of Odisha.
- Floating Gardens are ancient farming methods. These methods are similar and can be linked with hydroponic farming.
Schedule for Growing Plants Using Different Methods
| Week | Activities |
| Week 1 | Build a microgreen system. |
| Week 2 | Observe microgreen growth, build a wick method hydroponic system. |
| Week 3 | Harvest microgreens and record the yield, observe the growth of plants in the wick method, build DWC hydroponic system. |
| Week 4 | Record the growth of plants in the wick system, start making compost tea, observe the growth of plants in DWC. |
| Week 5 | Observe the growth of plants in the DWC system, build NFT hydroponic system, compost tea is ready for use. |
| Week 6 | Experiment with compost tea applications, observe the growth of plants in the DWC and NFT systems, experiment with water pH change. |
| Week 7 | Record the effect of compost tea and water pH on plant growth, maintain DWC and NFT systems, harvest and record the yield. |
Microgreens
- Microgreens are young seedlings of vegetables and herbs, harvested just after the emergence of the initial 2-4 leaves (size 1-3 inches).
- They are a quick and easy way to produce healthy sprouts in a compact space.
- Microgreens are a rich source of vitamins C, E, K, A and carotenoids.
- Microgreens can be produced from: cabbage, beetroot, fenugreek, mustard, spinach, coriander and wheat.
- Microgreens are eaten raw — used for garnishing salads, soups, sandwiches and pizza.
Wick Method
- The wick method is a simple hydroponic system made from used PET bottles — a great way to recycle waste.
- Plants are grown for full growth (not just 1-2 weeks like microgreens).
- Water travels from the reservoir to the plant roots through a cotton wick by capillary action.
- Capillary action is the process by which liquid moves through a narrow space like fibres of a wick, without the help of gravity.
System Maintenance
The wick method does not require much maintenance — no water pump or electrical equipment needed. Just add water to the reservoir regularly, check wick functioning and remove dead or older plants.
DWC Method or Bucket Method
- Deep Water Culture (DWC) is one of the easiest and most commonly used hydroponic methods.
- Plant roots are suspended in water containing essential nutrients.
- Expanded Polystyrene (EPS), thermocol or styrofoam sheets are used as a float to hold the plants above water.
- A bucket or water tub serves as the water reservoir. Net pots are used for planting seeds or seedlings.
- An aquarium aerator (air pump) is placed in the water to dissolve oxygen, which is essential for healthy root growth.
- Healthy roots should appear white. Brown roots indicate lack of dissolved oxygen.
System Maintenance
Proper functioning of the aerator is essential for healthy root growth. Healthy roots appear white, while brown roots indicate low dissolved oxygen (DO). The water remains free from algae when sunlight is blocked by covering the surface. Regular harvesting and timely replacement of old plants with new seedlings help maintain growth.
Internet Tip — Search using these keywords
- Do-It-Yourself (DIY) + methods of DWC hydroponics
- Instructions + DWC hydroponics
- DIY + beginners + DWC hydroponics
- DWC hydroponics + school learning activity
NFT Method
- In Nutrient Film Technique (NFT), plants stand in a shallow stream of water flowing as a thin film containing plant nutrients.
- Water continuously flows, so no air pump is needed to increase dissolved oxygen (unlike DWC).
- NFT uses less water and allows vertical stacking of pipes, making better use of space.
- It can be built in different shapes — horizontal stacking, vertical stacking, A-frame or pyramid.
- PVC pipes (76 mm diameter, 1-metre long) are used — each pipe can hold 6-7 plants.
- Sprouts are generally grown without light and provide extra nutrients. They are consumed raw along with roots in 2-5 days.
- Microgreens are grown with light, and extra nutrients can be added. They are consumed raw or as a garnish without roots in 10-15 days.
- The first leaves that appear during seed germination are called Seed Leaves (Cotyledons). They store food and nourish the young plant until it begins making its own food through photosynthesis. The leaves that develop afterward are called true leaves.
System Maintenance
The water level in pipes should be about half of the pipe’s diameter. If too low, plants roots may not reach the water, if too high, it may overflow. Proper slope adjustment of the pipes helps prevent overflow.
Liquid Organic Manure by Compost Tea
- Compost is made of decaying plants, food waste or manure, it contains essential plant nutrients.
- For hydroponics, we need liquid compost, also called compost tea.
- Good quality compost is dark brown to black in colour, has a pleasant earthy smell and a crumbly (like tea leaves) texture.
- Compost tea contains key nutrients: nitrogen, phosphorus, potash, magnesium, sulphur, etc.
- Jaggery or sugar is added to the compost tea as food for microbes — microbes help plant roots absorb nutrients faster.
Water pH
- pH is a measure of the acidity or basicity (alkalinity) of water.
- pH 7 is neutral; below 7 is acidic; above 7 is alkaline/basic.
- Nutrient mobility (transport of nutrients from water to plant body) is best when water pH is between 6.0 and 7.0.
- If pH is above 7 (alkaline), add a weak acid like acetic acid (vinegar) or citric acid (lime juice) to reduce it to 6.5-7.0.
- If pH is too low (acidic), add a base to bring it back to the optimal range.
- A pH paper strip is used to test the pH of water—the colour change on the strip indicates the pH value.
Important Water Quality Parameters
Apart from pH, other important water quality parameters are
- Dissolved Oxygen (DO): Oxygen dissolved in water.
- Total Dissolved Solids (TDS): Concentration of minerals/salts.
- Water Hardness: Dissolved calcium and magnesium.
- Electrical Conductivity Ability of water to conduct electricity depending on dissolved ions.
Acids Used for pH Adjustment
- Strong Acids such as phosphoric acid, sulfuric acid and nitric acid reduce pH in lower quantities but are harder and more dangerous to handle.
- Weak Acids such as citric acid, acetic acid and monoammonium phosphate are safer and easier to use for school hydroponics.
What Else You Can Do?
You can try the following to expand your learning
- Use a mobile phone to capture photos or videos of the steps and create a photo story or time-lapse video of your hydroponic systems.
- Decorate wick hydroponic bottles and present them as creative gifts to visitors or guests.
- Experiment with different growth media such as soil, sand, cocopeat, or their mixtures.
- Compare temperature, humidity, and light intensity inside and outside a nursery using mobile apps like MAUSAM or a lux meter.
- Display hydroponic models and posters of your learning during the Kaushal Mela.
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