Crop-Specific Strategies in Hydroponics
Root Zone Optimization
In hydroponics, the root zone is the absolute heart of the cultivation system. Unlike soil-based cultivation, the complete control over growth conditions requires precise strategies tailored to the respective crop type. The decisive factor here is the oxygen supply to the roots.
Leafy Vegetables & Herbs (Lettuce, Spinach, Basil)
Strategy: Shallow Systems with High Gas Exchange
These crops with shallow, fibrous root systems thrive in systems with passive but efficient gas exchange.
Concrete Facts:
- Optimal NFT Parameters: Film thickness of 1-2 cm and slope of 1-3% for turbulent flow
- Oxygen Requirement: Lower than fruiting vegetables, but critical for tipburn prevention
- Systems: Nutrient Film Technique (NFT) and Floating-Raft systems ideal
Reference:
Goto, E., & Takakura, T. (1992). Prevention of lettuce tipburn by supplying air to inner leaves. Transactions of the ASAE, 35(2), 641-645.
Fruiting Vegetables (Tomato, Cucumber, Pepper)
Strategy: Active Aeration and Volume Control
Crops with high biomass production require active oxygen supply for their deep root systems.
Concrete Facts:
- Oxygen Enrichment: Target value > 8 mg/L in DWC systems using membrane diffusers
- System Choice: Deep Water Culture (DWC) or substrate systems with drainage
- Control: Continuous monitoring of dissolved oxygen concentration
Reference:
Bonachela, S., et al. (2020). Oxigenación de la solución nutritiva en sistemas hidropónicos cerrados de tomate en invernadero. Acta Horticulturae, 1273, 87-94.
Root Vegetables (Radish, Carrot)
Strategy: Substrate-Based Systems
Crops with tuber formation require physical support through special substrate mixtures.
Concrete Facts:
- Substrate Optimization: Mixtures of coconut coir and perlite (50:50) for ideal air-water balance
- Air Pore Volume: Crucial for uniform tuber development
- Irrigation: Drip irrigation with drainage control to avoid waterlogging
Reference:
Gruda, N., & Schnitzler, W. H. (2004). Suitability of wood fiber substrates for production of vegetable transplants. Scientia Horticulturae, 100(1-4), 333-340.
Further Reading
- Resh, H. M. (2022): Hydroponic Food Production: A Definitive Guidebook for the Advanced Home Gardener and the Commercial Hydroponic Grower (9th ed.). CRC Press.
- Sonneveld, C., & Voogt, W. (2009): Plant Nutrition of Greenhouse Crops. Springer.
- Savvas, D., & Gruda, N. (2018): Application of soilless culture technologies in the modern greenhouse industry. European Journal of Horticultural Science, 83(5), 280-293.
Next article in the series: Economic Viability of Hydroponic Systems: Energy vs. Yield and ROI Calculations
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