The cultivation of medicinal plants in aquaponic systems requires specific knowledge about their nutrient requirements and growth conditions. This article examines the suitability of selected medicinal plants for cultivation in water recirculation systems.
Find more about medicinal plants in our separate article series on Medicinal Plants, Effects, Propagation, and Their Processing.
Specifics of Medicinal Plants in Aquaponic Systems
Medicinal plants have specific requirements for their growth conditions that must be considered when integrating them into aquaponic systems:
Advantages
- Precise control of nutrient supply
- Lower risk of soil contamination
- Controlled growth conditions
- Higher purity of active compounds
- Year-round cultivation possible
Challenges
- Species-specific nutrient needs
- Sensitivity to nutrient imbalances
- Differing pH requirements
- Varying tolerance to moisture
- Specific light needs
Suitability of Selected Medicinal Plants
Examination of the cultivation suitability of various medicinal plants in aquaponic systems:
Overview of Medicinal Plants and Their Suitability
| Plant | Suitability | Nutrient Requirement | Particularities |
|---|---|---|---|
| Stinging Nettle Urtica dioica |
Well suited | High (Heavy feeder) | Requires lots of nitrogen, thrives well in nutrient-rich water. Regular pruning required. |
| Echinacea Echinacea purpurea |
Limited | Medium | Sensitive to waterlogging. Requires well-aerated substrate. Perennial but winter-hardy. |
| Chamomile Matricaria chamomilla |
Well suited | Low to Medium | Annual, prefers moderate nutrient supply. Sensitive to excessively high nitrate levels. |
| Lavender Lavandula angustifolia |
Poorly suited | Very Low | Requires dry conditions and well-draining substrate. Sensitive to root rot in hydroponic systems. |
| Lemon Balm Melissa officinalis |
Very good | Medium | Grows excellently in hydroponic systems. Fast growth, regular pruning required. |
| Orange Mint Mentha × piperita citrata |
Very good | Medium to High | Robust, fast-growing. Requires sufficient space or isolation, as it spreads readily. |
| Peppermint Mentha × piperita |
Very good | Medium to High | Ideal plant for aquaponics. Fast growth, high water demand, tolerates various conditions. |
| Rosemary Rosmarinus officinalis |
Poorly suited | Low | Mediterranean plant with low nutrient demand and tolerance for drought. Prone to root rot in NFT systems. |
| Sage Salvia officinalis |
Limited | Low | Conditionally suitable. Requires excellent drainage and moderate moisture. Possible in media beds with coarse substrate. |
| Thyme Thymus vulgaris |
Poorly suited | Very Low | Mediterranean plant with high drought tolerance. Usually not successful in conventional aquaponic systems. |
Adaptations for Less Suitable Species
For Mediterranean herbs with low nutrient tolerance, special system adaptations can be made:
System Modifications
- Separate Loops: Creation of subsystems with reduced nutrient availability
- Drip Irrigation: Targeted, reduced irrigation for drought-tolerant species
- Substrate Selection: Use of coarse mineral substrate with excellent drainage
- pH Regulation: Targeted increase of pH for Mediterranean herbs
Nutrient Management
- Dilution: Targeted dilution of nutrient content for undemanding species
- Separate Feeding: Isolated nutrient supply for different plant groups
- Timed Supply: Intermittent nutrient supply for species with low demand
- Buffer Zones: Integration of plants with different needs into separate zones
Active Compound Content in Aquaponic Cultivation
Studies show varying effects of hydroponic cultivation on active compound contents:
Comparison of Active Compound Production
| Plant | Active Compound | Aquaponics vs. Soil Culture | Optimization Possibilities |
|---|---|---|---|
| Lemon Balm | Essential Oils | Higher concentration with moderate nutrient supply | Mild stress by reduced irrigation before harvest |
| Peppermint | Menthol | Comparable or slightly increased | Slight reduction of nitrogen supply before flowering |
| Echinacea | Alkamides | Variable, dependent on root health | Good aeration of the root zone crucial |
| Chamomile | Bisabolol | Higher values under controlled conditions | Even supply, no stress periods |
Practical Tips for Medicinal Plant Cultivation
Recommended Species for Beginners
- Peppermint - robust and adaptable
- Lemon Balm - fast growth
- Chamomile - moderate requirements
- Stinging Nettle - high nutrient tolerance
Harvest Optimization
- Harvest in the morning after the dew has dried
- Before full bloom for maximum active compound concentration
- Slight reduction of irrigation 24-48 hours before harvest
Note on Active Compound Quality
The quality of active compounds in medicinal plants is influenced by many factors. Aquaponic systems offer the possibility to control these factors precisely, but require exact knowledge of the specific needs of each plant species.
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