Guide to growing aquatic plants emersed: differences between submersed and emersed forms, benefits, equipment, humidity management, and recommended species.
Key Takeaways
Guide to growing aquatic plants emersed: differences between submersed and emersed forms, benefits, equipment, humidity management, and recommended species.
When thinking of aquatic plants, we typically imagine plants grown underwater, but many aquatic plants can actually be grown above water. This is called "emersed cultivation" or "emerged cultivation." Emersed cultivation offers many benefits not found in submerged cultivation, and its popularity is increasing among aquatic plant enthusiasts.
Most aquatic plants grow in areas with fluctuating water levels in nature and have the ability to adapt to both submerged and emersed environments. Leaves that develop underwater are called "submerged leaves (submersed)" while leaves that develop above water are called "emersed leaves (emerged)."
Even within the same species, submerged and emersed leaves look very different. Generally, emersed leaves are thicker and stiffer than submerged leaves and have a darker green color. Submerged leaves are characteristically thin and soft, with a delicate appearance due to high light transparency. In the case of Rotala rotundifolia, submerged leaves are thin, reddish leaves, but emersed leaves are rounded, green leaves. This ability to display completely different forms in emersed and submerged environments is what makes aquatic plants so fascinating.
No Concern About Algae The greatest benefit of emersed cultivation is that there is no algae problem that plagues submerged cultivation. You are completely freed from the most stressful part of aquarium management—algae removal.
Easy Maintenance Submerged cultivation requires many devices and knowledge, such as filters, CO2 injection systems, and water quality management. In contrast, emersed cultivation is simple—just fill a pot with soil and maintain water at the base. Lighting can often be provided by natural light from a windowsill, requiring no electricity costs.
Faster Growth Since the air contains approximately 50 times more CO2 than water, aquatic plants grow much faster in emersed cultivation. If you want to efficiently propagate aquatic plants for stock, emersed cultivation has a clear advantage.
Enjoy Flowers You can observe flowers of aquatic plants in emersed cultivation that are rarely seen underwater. Enjoying rare flowers such as the white blooms of Bucephalandra and the unique tubular flowers of Cryptocoryne—sights unseen underwater—is a unique pleasure of emersed cultivation.
Manage Multiple Species in Limited Space Since you can manage one species at a time in small pots or containers, you can collect many species in limited space. This is suitable for those who don't have room for multiple aquariums.
Very little special equipment is needed to begin emersed cultivation.
Containers Any container that holds water can be used—plastic pots, pudding cups, plastic cases, storage containers, and more. Transparent containers are recommended as they make humidity management easier. Using a glass case designed for paludariums allows you to enjoy it as interior décor as well.
Substrate Small-grain akadama clay is the most common and readily available substrate. You can also use aquatic plant soil as-is. Clay soil (arakida clay) is also suitable for aquatic plant emersed cultivation and, being nutrient-rich, promotes good growth.
Semi-Hydroponic Tray This is a tray that maintains the pot's base in constantly moist water. Use plastic saucers or shallow trays. The water depth should be approximately 1–3 cm above the pot base, being careful not to submerge the entire pot.
Humidity-Maintaining Cover For aquatic plants that prefer high humidity, maintain humidity by covering with plastic wrap or a lid. Since a complete lack of ventilation can cause mold, leave small gaps or ventilate once daily.
1. Prepare Containers and Substrate Add 3–5 cm of substrate to the container and pour water to moisten the entire substrate. The ideal water level is just slightly visible above the substrate surface.
2. Plant Aquatic Plants Plant aquatic plants as-is if obtained in submersed form. Submersed leaves may rot or wither when transitioning to an emersed environment, but new emersed leaves will develop if the rhizome or roots remain alive. If obtained as emersed leaves, simply plant them as-is.
3. Manage Humidity Humidity is especially important immediately after planting. Cover the container with plastic wrap to maintain humidity above 80%. Once the emersed leaves stabilize, gradually remove the wrap to acclimate them to normal indoor humidity.
4. Light and Temperature Place in a bright location by a window or use a small LED light. Direct sunlight can cause the container to overheat in summer, so bright light filtered through sheer curtains is ideal. The optimal temperature is 20–28°C; in winter, be careful not to drop below 15°C.
5. Fertilizer and Water Management Replenish the semi-hydroponic water as it decreases, and perform complete water changes approximately once every two weeks to keep it clean. Add fertilizer by diluting liquid fertilizer in the semi-hydroponic water or by mixing substrate fertilizer into the soil. Since growth is faster in emersed cultivation than submerged, be careful not to run out of fertilizer.
Not all aquatic plants are suitable for emersed cultivation. Below are species that are particularly easy to grow emersed.
In contrast, obligate aquatic species such as Vallisneria and Hornwort are difficult or impossible to grow emersed.
When introducing aquatic plants propagated through emersed cultivation to an aquarium, a transition period from emersed to submersed leaves is necessary. If you place emersed-form plants directly in the aquarium, old leaves will fall off, but new submersed leaves will develop. The transition period varies by species but typically takes 2–4 weeks. During this time, the appearance may look somewhat untidy, but be patient.
At Br-choku, you can purchase aquatic plants in both emersed and submersed form from breeders with expertise in emersed aquatic plant cultivation. A major advantage is being able to ask experienced breeders directly about tips for emersed cultivation and species-specific precautions.
Find Aquatic Plants listings related to this article on BreederDirect. Buy directly from verified breeders.
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