Database results:
examBoard: Pearson Edexcel
examType: IGCSE
lessonTitle: Glasshouse Crop Production
Glasshouse crop production (also called protected cultivation) is a method of growing plants in structures that provide a controlled environment. These structures can be made of glass or plastic and allow farmers to grow crops throughout the year, regardless of outside weather conditions.
Key Definitions:
Glasshouses: Traditional structures made of glass panels supported by metal frames. Excellent light transmission but expensive to build and maintain.
Polytunnels: Curved structures covered with polythene. Cheaper than glasshouses but less durable and provide less precise environmental control.
Cloches: Small portable covers used to protect individual plants or rows, often used for early season growing.
Year-round growing: Crops can be grown regardless of season or outside weather.
Higher yields: Controlled conditions lead to faster growth and higher productivity.
Protection from pests: Physical barrier against many insects and animals.
Water efficiency: Reduced water loss through evaporation and precise irrigation.
The success of glasshouse crop production depends on controlling various environmental factors to create optimal growing conditions for plants. Modern glasshouses use sophisticated technology to monitor and adjust these conditions.
Control methods: Heating systems (gas, electric, or biomass), ventilation, shade screens and cooling systems.
Importance: Different crops have specific temperature requirements for optimal growth. Temperature affects photosynthesis rate, respiration and overall plant development.
Control methods: Ventilation, misting systems and dehumidifiers.
Importance: High humidity can promote fungal diseases, while low humidity increases water stress. Optimal humidity levels support healthy plant growth and reduce disease risk.
Control methods: Supplementary lighting (LED or high-pressure sodium lamps), shade screens and glass/plastic coverings with specific light transmission properties.
Importance: Light is essential for photosynthesis. Light intensity, duration and spectrum all affect plant growth and development.
Control methods: CO₂ enrichment systems that release additional carbon dioxide into the glasshouse atmosphere.
Importance: CO₂ is a key ingredient in photosynthesis. Increasing CO₂ levels (typically to 1000-1500 ppm) can significantly boost plant growth and yield.
Control methods: Automated irrigation systems, drip irrigation, hydroponics and nutrient film technique (NFT).
Importance: Precise control of water and nutrients ensures optimal plant growth while minimizing waste and preventing nutrient deficiencies or toxicities.
Modern glasshouses use various growing systems, each with specific advantages for different crops and situations.
Traditional soil beds: Plants grown directly in soil within the glasshouse.
Raised beds: Improved drainage and soil management.
Considerations: Soil sterilization between crops is often necessary to control soil-borne diseases and pests.
Hydroponics: Plants grown in nutrient solution without soil.
Growing media: Materials like rockwool, perlite, coconut coir, or vermiculite that provide physical support for plants.
Advantages: Better control of nutrients, reduced disease risk and often higher yields.
Thanet Earth is one of the UK's largest glasshouse complexes, covering 90 hectares. It produces tomatoes, peppers and cucumbers year-round using hydroponic systems. The facility captures rainwater for irrigation and uses combined heat and power (CHP) systems to generate electricity while providing heat and CO₂ for the crops. This integrated approach has made it one of the most efficient and sustainable large-scale glasshouse operations in Europe.
While glasshouses provide some protection against pests and diseases, the warm, humid environment can also create ideal conditions for certain problems. Modern glasshouse production uses integrated pest management (IPM) approaches.
Definition: Using natural enemies to control pest populations.
Examples:
Advantages: Environmentally friendly, no chemical residues, pests don't develop resistance.
Chemical controls: Pesticides, fungicides and other treatments used when necessary, often as a last resort.
Cultural controls:
Glasshouse production involves significant economic and environmental trade-offs that must be carefully considered.
High initial investment: Building and equipping glasshouses requires substantial capital.
Energy costs: Heating, lighting and climate control systems consume significant energy.
Labour requirements: Despite automation, skilled labour is needed for crop management.
Market advantages: Year-round production, consistent quality and premium prices for out-of-season produce.
Energy use: Traditional glasshouses have high carbon footprints due to heating requirements.
Water efficiency: Closed systems can use up to 90% less water than field production.
Land use: Higher yields per unit area reduce land requirements compared to field production.
Waste management: Plastic and other materials require proper disposal or recycling.
The technology of glasshouse crop production continues to evolve rapidly, with several exciting innovations improving efficiency and sustainability.
Energy-efficient LED lights can be tuned to specific wavelengths that promote plant growth. This allows for precise light recipes tailored to different crops and growth stages.
Robots and automated systems for planting, harvesting and crop monitoring reduce labour costs and improve precision. Some facilities use AI to optimize growing conditions.
Integration of renewable energy sources like solar panels, geothermal heating and biomass boilers to reduce carbon footprint and energy costs.
Vertical farming takes the principles of glasshouse production even further by stacking growing systems in layers. These systems typically use hydroponics or aeroponics with LED lighting and can be established in urban areas, even in repurposed buildings. While energy intensive, they offer extremely high productivity per unit area and can be located very close to consumers, reducing food miles. Several commercial vertical farms now operate in the UK, primarily producing leafy greens, herbs and microgreens.
Log in to track your progress and mark lessons as complete!
Login NowDon't have an account? Sign up here.