What is hydroponics?
Hydroponics is a method of plant cultivation in which plants obtain their nutrients from a nutrient solution instead of soil. The term is derived from the Greek "hydro" for water and the Latin "cultura" for cultivation. Globally, this cultivation method is used on a wide range of scales, from large commercial operations to houseplants in one's own home. The advantages lie primarily in the precise control over nutrient supply and the efficient use of water. Furthermore, plants in hydroponics can often grow more vigorously.
In everyday life, hydroponics and water culture are often used interchangeably. Strictly speaking, however, both methods differ in terms of the substrate. In hydroponics, the roots grow in a mineral material such as expanded clay, perlite, vermiculite, coconut fiber, or rock wool. This provides support for the plant and stores water, while the nutrient solution sits in the lower part of the container. In water culture, the plant does not use any substrate at all. Its roots sit directly in the water, usually in a glass vase. This variant is particularly suitable for cuttings and smaller plants.
Advantages of hydroponics
- Efficient use of water: Hydroponics uses up to 90% less water than traditional soil cultivation because the water is recycled in a closed system.
- Control over nutrients: The nutrient concentration can be precisely adjusted to promote optimal plant growth.
- Faster plant growth: Due to the constant availability of nutrients and water, plants can grow faster in hydroponic systems.
- Space saving: Hydroponics allows for the cultivation of plants in vertical systems, which is particularly advantageous in urban areas.
- Reduced pest and disease infestation: Without soil, the risk of soil-borne diseases and pests is lower.
Different types of hydroponic systems
There are several types of hydroponic systems that differ in their complexity and application. Among the most common systems are:
1. Nutrient Film Technique (NFT)
In this system, a thin layer of nutrient solution flows continuously over the roots of the plants, which sit in a slightly inclined channel. This system is particularly efficient because the roots are constantly supplied with oxygen and nutrient uptake is maximized.
2. Deep Water Culture (DWC)
In the DWC method, the plant roots are submerged directly in a deep water-nutrient solution. An air stone provides the necessary aeration of the solution to supply the roots with sufficient oxygen. This system is easy to operate and is well-suited for growing leafy greens and herbs.
3. Flood and Drain system
In this system, the plant pots are periodically flooded with nutrient solution and then drained. This allows for optimal nutrient supply and aeration of the roots. The flood and drain system is versatile and can be used for various types of plants.
4. Drip system
Here, the nutrient solution is delivered directly to the plant roots through a drip irrigation line. The drip system can be operated either continuously or intermittently and offers precise control over nutrient delivery.
Nutrient solutions in hydroponics
The nutrient solution is the heart of every hydroponic system. Without soil, all nutrients come from the water. A good nutrient solution for plants therefore contains all the elements they need to grow and is crucial for the success of a hydroponic system. It should contain:
- Macronutrients: Nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and sulfur (S).
- Micronutrients: Iron (Fe), manganese (Mn), zinc (Zn), copper (Cu), boron (B), molybdenum (Mo), and chlorine (Cl).
Fertilizer for hydroponics
The nutrient solution should be monitored and adjusted regularly to ensure that the plants always find optimal conditions. Liquid hydroponic fertilizer is added to the water according to the manufacturer's instructions and is usually lower in dosage than regular flower fertilizer. Ion-exchange fertilizer, on the other hand, acts as a long-term fertilizer. It releases nutrients into the water gradually and, in return, binds salts from the tap water. Regular flower fertilizer is only conditionally suitable because salts can accumulate in the substrate.
Nutrient solution measurements
Two measurements indicate whether the nutrient solution is suitable for hydroponics. The pH value indicates how acidic or alkaline the solution is. Most plants absorb nutrients best at a slightly acidic value between approximately 5.5 and 6.5. The EC value measures electrical conductivity and thus the amount of dissolved salts. A high value means a highly concentrated nutrient solution. Plants in active hydroponic systems therefore require regular monitoring of both values. For houseplants in passive hydroponics, it is usually sufficient to follow the fertilizer dosage and flush the substrate occasionally.
Practical tips for hydroponics
- Choosing the right system: Select the hydroponic system that best fits the needs of your plants and your available space.
- Monitoring the nutrient solution: Regularly check the pH and EC (electrical conductivity) values of the nutrient solution to ensure they are within the optimal range.
- Lighting: Plants in hydroponic systems require sufficient light. Use artificial lighting such as LED lamps if natural light is insufficient.
- Oxygen supply: Ensure that the roots are sufficiently supplied with oxygen, especially in Deep Water Culture systems.
- Temperature and humidity: Maintain the ambient temperature and humidity at an optimal level to promote plant growth.
Hydroponics offers an innovative and efficient method of plant cultivation that provides many advantages over traditional soil cultivation. With the right selection of systems, careful monitoring of nutrient solutions, and attention to the needs of your plants, you can successfully grow healthy and productive plants in a hydroponic environment. In our blog post on hydroponics, you can learn more about how you can keep your houseplants in water long-term.
