Important Definitions
Q1. What is hydroponics and why is it useful?
Answer: Hydroponics is a method of growing plants without soil using nutrient-rich water. It is useful as it saves land, uses less water, gives faster growth, and helps produce healthy food in limited space like cities.
Q2. Why is hydroponics called a precision farming technique?
A: Hydroponics is called a precision farming technique because it allows farmers to supply accurate amounts of water, nutrients, and light to plants. This controlled method reduces wastage and increases crop yield and quality significantly.
Q3. What are microgreens and how are they used?
A: Microgreens are young seedlings of vegetables and herbs harvested after the first 2–4 leaves appear. They are rich in nutrients and are used raw in salads, sandwiches, soups, and as garnish to enhance taste.
Q4. Differentiate between seed leaves and true leaves.
A: Seed leaves or cotyledons appear first after germination and provide stored food to the young plant. True leaves appear after seed leaves and perform photosynthesis to produce food for the growing plant’s further development.
Q5. What is capillary action and its use in hydroponics?
A: Capillary action is the upward movement of water through narrow spaces like cotton threads. In the wick hydroponic method, this action carries water and nutrients from the bottom reservoir to plant roots above.
Q6. Name the three hydroponic systems mentioned in the book.
A: The three hydroponic systems mentioned are Wick Method, Deep Water Culture (DWC), and Nutrient Film Technique (NFT). All three help in growing plants without soil using water-based nutrient solutions in different ways.
Q7. How is the Wick Method hydroponic system built?
A: In the wick method, a PET bottle is cut into two parts. A cotton wick is inserted through the cap, the top is filled with growing medium, and the bottom holds water that moistens the roots.
Q8. What is the Deep Water Culture (DWC) system?
A: In the DWC system, plant roots are suspended in nutrient-rich water. A styrofoam sheet holds net pots, and an aerator supplies oxygen. This allows continuous nutrient absorption and faster plant growth without soil.
Q9. What is the Nutrient Film Technique (NFT) system?
A: In NFT, plants are placed in holes on PVC pipes. A thin film of nutrient-rich water flows continuously near the roots, providing nutrients and oxygen. It uses less water and supports vertical stacking of plants.
Q10. Why is an aerator used in DWC but not in NFT?
A: An aerator is used in DWC to dissolve oxygen in still water for healthy roots. NFT has continuously flowing water which mixes with air naturally, so an aerator is not needed in the system.
Q11. What is compost tea and how is it prepared?
A: Compost tea is a liquid organic manure. It is prepared by soaking compost in water with jaggery and aerating it for 2–3 days. It contains nutrients and beneficial microbes that promote plant growth.
Q12. Why is maintaining pH important in hydroponics?
A: Maintaining pH is important because it affects how easily plants absorb nutrients from water. If pH is too high or low, plants cannot absorb nutrients properly, leading to poor growth or nutrient deficiency.
Q13. What is the ideal pH range for hydroponic water?
A: The ideal pH range is 6.0 to 7.0. In this slightly acidic to neutral range, plants can easily absorb most essential nutrients from the water, supporting healthy and balanced growth in hydroponic systems.
Q14. How can you lower the pH of hydroponic water?
A: To lower pH, weak acids like vinegar (acetic acid) or citric acid can be added in small amounts to the water. This reduces alkalinity and helps maintain the ideal pH for plant nutrient absorption.
Q15. List two advantages of hydroponics.
A: (1) Hydroponics uses less water by recirculating it, which conserves water.
(2) It allows vertical farming, producing more food in less space, which is helpful in cities or areas with limited farming land.
Q16. List two disadvantages of hydroponics.
A: (1) It needs technical knowledge and careful monitoring of water quality and pH.
(2) It requires an initial high setup cost for equipment like pumps, aerators, and nutrient solutions compared to traditional soil farming.
Q17. What safety measures should be followed during hydroponic activities?
A: Always wear gloves, handle sharp tools carefully, use electrical gadgets like aerators under teacher’s supervision, and follow internet safety rules. These precautions prevent injuries and ensure safe working with hydroponic systems in school.
Q18. How do microbes help in hydroponics?
A: Microbes break down complex organic matter into simpler forms so plant roots can absorb nutrients easily. They also protect plants from diseases and support communication between plants, promoting healthy growth in hydroponic systems.
Q19. Name three materials used in hydroponic systems.
A: Three commonly used materials are:
- Net pots for holding plants
- Cocopeat or coco coir as a growth medium
- Styrofoam sheet or bucket as support for plants above water solution.
Q20. Mention three careers related to hydroponics.
A: Three careers are:
- Agricultural scientist, who develops new farming methods
- Botanist, who studies plant growth and health
- Gardener or urban farmer, who grows and maintains plants using hydroponic systems in homes or schools.
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