Hydroponic Production

Unit Essential Question

Unit EQ: What influences the decisions of hydroponic growers?

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Future Topics:

Types of systems, nutrient solutions, rooting media, water quality, lighting systems, management/maintenance, food safety/marketing

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Major Grade: Unit Test and Partner Project Hobby Design Model

Hydroponic Production

What do plants need to survive?

What does “hydroponic” mean?

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How would you define “hydroponics?

Now, what you want to know?

Introduction to Hydroponics

• Lesson EQ:
• What allows plants to grow primarily in water?
• Objective:
• Explain the difference between hydroponics and soilless culture
• Recognize examples of Controlled Environment Agriculture (CEA)
• Compare and Contrast advantages and disadvantages of hydroponic production
• Report 4 environmental factors influencing plant growth
• Summarize the 6 parts necessary for successful plant production

Journey to Hydroponics

Hydroponic Introduction

• Combination of two Greek words—
• hydro means “water”
• ponics means “labor.”
• Hydroponic:
• Form of soilless culture using a technique where plants are grown in an inert medium and supplied with a nutrient solution

Hydroponic Growing Medium:

• Inert.
• Relatively unimportant component of the plant nutrition program
• Has little effect on pH
• Does not supply nutrients directly and has no cation exchange capacity.

Technically...

Hydroponics require:

• No soil
• (Almost) inert growing medium
• Nutrient solution supplying all the plant nutrients and determines the pH of the medium

Hydroponics does NOT require:

• A greenhouse or warehouse
• Recirculating water/nutrient solution
• Flowing water
• Roots growing freely in water

Public connection hydroponics with the broader concept of Controlled Environment Agriculture

Controlled Environmental Agriculture (CEA)

• Indoor Plant Factory
• Controlled:
• Temperature
• Light
• Carbon Dioxide
• Water
• Hydroponic or soilless culture (no soil)
• Zero erosion, run-off

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Inquiry Activity

• Using RELIABLE sources, list out at least 4 advantages and 4 disadvantages of hydroponic production
• You can research hydroponic systems and make predictions about the benefits and drawbacks of growing crops hydroponically
• After 10 minutes of independent work, you can confer with a neighbor about their findings and predictions
• Use notebook paper to record your list

What did you discover about Hydroponic Systems?

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Share with class

Advantages

1. Hydroponics does not use soil so harmful insects that live in soils cannot damage hydroponic crops
2. Do not have weed seeds that might germinate and compete with crops for water, nutrients, and light.

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Advantages

3. Hydroponic systems allow for every plant’s optimal nutrient needs to be addressed.

• The plants do not have to compete for available nutrients and can therefore be placed closer together.
• Amount of nutrients needed by plants can be adjusted as they grow
• Hydroponic systems allow the pH levels available to plants to be adjusted quickly

Advantages

4. Hydroponics allows for high-quality yields in parts of the world that have non-productive land or poor growing conditions.

• Urban (contaminated soils, food deserts)
• Contaminated soils: nematodes, pathogens
• Lack of soil and/or water: deserts
• Cold winter locations

Disadvantages

1. The initial investment in a commercial hydroponic system is high

2. Some diseases can spread rapidly throughout a hydroponic system.

3. Many hydroponic systems are set up in greenhouses.

• Flower pollination can be difficult in greenhouses.

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Disadvantages

4. High potential for nutrient insufficiencies

5. No buffer for pH, nutrients, water, CO2, oxygens, stressors (Little room for error)

6. Continuous power required

4 Environmental Factors Influence on Plant Growth

1. Light
2. Temperature
3. Humidity
4. CO2

• Photosynthesis - creating energy
• Cellular Respiration - using energy
• Transpiration - water movement in plants
• Nutrient Uptake

Photosynthesis

• Uses: light, CO2, water
• Quality and Quantity of each affect the output
• Create: oxygen, sugar (glucose - energy)
• Increase light intensity = greater use of CO2

Respiration

• At night or when light not available
• Uses: sugars and oxygen
• Create: CO2
• Affected by the level of water, temperature, CO2 and oxygen
• Decrease temperature = decrease respiration

Temperature

Water Uptake & Transpiration

• Water moves through xylem along a water potential gradient
• Trying to reach equilibrium
• High humidity (water in air)
• Lower transpiration
• Less water stress
• Higher plant temperatures
• Higher disease pressures
• Since some nutrients need water to be take up, water’s ability to move is very important (calcium & boron)

Transpiration

• Water vapor OUT: transpiration, evaporative cooling, water flows from roots to shoots
• Carbon Dioxide IN: photosynthesis > carbs > energy > growth/maintenance
• Stomata regulate CO2 uptake and water lost from leaves
• Stomata open to allow CO2 into leaf during sunlight and adequate water
• Stomata close to reduce water loss at night and during water stress

6 Parts of Successful Plant Production

1. Genetics
2. Environment
3. Nutrients (12 essential)
4. Water
5. Cultural Practices
1. Crop manipulation: leaf removal, fruit thinning, trellising
6. Disease/Pest Management
• Sanitation, scouting