I've been growing aquarium plants emersed for several years now, and figured I would make an article for anyone interested in doing the same. Growing aquarium plants in an emersed setup is a great way to quickly propagate plants and ensure they're strong and healthy before planting your tank. With this growth method, you only have to buy a few plants to ensure a thick jungle for your fish to live in.
A sword that has been lifted to the surface
to stimulate emersed growth before being
moved to an emersed container
Which plants can grow in an emersed setup?
There are hundreds of types of aquarium plants in the hobby, and you can grow the majority of them like this. However, not all plants can be grown this way. Here is a list of some plants that have done well for me in emersed bins & tanks over the years:
Substrate and Nutrients
To ensure that your emersed plants grow as fast and robust as possible, you need a proper substrate. There are many ways to achieve this, however I've had the most success using any of these three different methods.
The first method is to use a layer of organic, chemical-free potting soil. This will work similarly to a dirted aquarium, but there is no need for a sand or gravel cap. It works wonderfully for around a year or two, but after that point must be replaced. If not replaced, it'll begin to compact and suffocate your plants' roots, along with becoming a breeding area for anaerobic bacteria and mold. It also becomes depleted in nutrients over time, so it's best to just replace it.
The second method is to place a few pellets of Osmocote fertilizer under a cap of sand or gravel. This also works with aquarium root tabs and equivalent organic, slow-release fertilizers, but I've only tried Osmocote for this method. The pellets last about a year for smaller, lighter feeding plants such as dwarf Sagittaria, around six months for average feeders such as crypts, java fern, bolbitis, and hydrocotyle, and around three months for large, heavy feeders such as swords, Alternanthera, Pogostemon, and water sprite.
The third, and most often seen method for growing emersed plants is to use planted tank substrate such as Flourite, Stratum, or Aquasoil. This way is very successful, as you can probably imagine, but can be expensive. If you have extra planted tank substrate lying around, by all means use it, but potting soil works just as well. I've tried this method a few times, and it tends to be the longest lasting substrate. If you're planning to keep the plants in your container for more than a year, this is the best way for you.
An emersed Cryptocoryne grown in potting soil within a springtail breeding container
Humidity
Humidity is extremely important for plants transitioning from aquatic to terrestrial growth. If inadequate humidity is provided, the plants will dry out and die. A good way to provide humidity is daily misting. This keeps the leaves in contact with water, which is crucial to keep them functional for photosynthesis until the plant can grow emersed leaves.
Misting, however, is not enough to keep the plants water needs fully satisfied. Many require some form of covering over their container to hold in moisture. A piece of glass or acrylic works well, but plastic wrap will do for a few weeks. Combine the misting and covering for optimal water retention.
I also like to add a bit of water to the containers. Just enough to fill it up to about a half-inch above the substrate level. This will ensure that if your lid is ever knocked off or broken, the roots of the plant will stay hydrated in order to grow back whatever leaves were damaged.
For some plants, constant covering is essential. For others, however, exposure to air isn't a super big deal. For plants that are still adjusting to terrestrial growth, lack of humidity is a death sentence. For something like a fully established sword, it's nothing. Some people grow swords, dwarf sag, and anubias with no covering at all because they can handle lower humidity. The container should still always have a tiny bit of water in the bottom, though.
Lighting
The light needs for emersed plants are relatively undemanding. A simple LED strip will do the job, although the growth will always be faster with a better light. Even an east facing window will work. If you do use a window, make sure that it's one with little or no direct sun and plenty of indirect light. Direct sun will burn the plants. A tiny bit is ok in the morning or very late afternoon, but nothing more. I use both LED grow lights and window light to grow my plants. They grow very well like this despite the lack of particularly fancy lighting.
Common Pests
Unfortunately, Emersed plants are subject to many of the same pests as immersed plants. As this is a very humid environment, algae and snails can both still spread within these containers. The best way to prevent snail infestation is to do the same as you would with an aquarium. A bleach or peroxide dip will kill off any eggs or snails on the plant.
There is no true way to prevent algae infestation, other than proper ventilation, which will be detailed in the next section. If algae has already taken hold, you don't need to worry. Unlike in aquariums, the algae here won't grow on plant leaves and block light. As long as you keep the top of the container where light comes in free of algae, the plants will do fine. Algae also grows much more slowly out of water, so you don't have to remove it too often.
Ventilation
As mentioned in the section above, ventilation is very important for emersed plants. To avoid mold and algae growth, proper airflow is needed. There are a few ways that I've used to achieve a proper balance between humidity and air.
The first method is to simply add holes to the top. For glass, you may need a special drill bit, but acrylic and plastic are easy enough. Don't add too many holes, as this will let too much water out, but a few are fine. I would do about 3-5 holes lengthwise along the middle of a 2ft long container. Mist this around twice a week, and it should work nicely.
The second method is to break off the corner of the top. For glass and acrylic I usually don't do this, but for plastic, you can just saw the corner off. Since this is a larger hole, it means you have to mist more often. Every other day should be ok.
The third method is my least favorite. It involves using a small fan to keep the air circulating. It does provide superior circulation for the plants, but is just more complicated than necessary for most people. The plants don't do any worse with holes in the top, so unless you need to, there is no reason to use a fan. It is a good option for someone who can't mist often or has to run lots of emersed containers, as you only need one small hole in the top for this to work, but is entirely unnecessary for anyone who just has a few containers and a few extra minutes to mist.
A Bolbitis heudelotii I recently moved to my dart frog vivarium
This is the information I have gained after years of experience with emersed plants. It may seem complicated, but it can actually be a very easy and fun way to multiply your plants. Doing this can get you dozens more plants for not just cheap, but possibly free. I hope this was helpful.
(sorry this is so long)
A sword that has been lifted to the surface
to stimulate emersed growth before being
moved to an emersed container
Which plants can grow in an emersed setup?
There are hundreds of types of aquarium plants in the hobby, and you can grow the majority of them like this. However, not all plants can be grown this way. Here is a list of some plants that have done well for me in emersed bins & tanks over the years:
- java fern
- Anubias spp.
- swords
- Cryptocoryne spp.
- Bolbitis spp.
- Hygrophila spp.
- Bacopa spp.
- Ludwigia spp.
- Pogostemon spp.
- Alternanthera spp.
- Hydrocotyle spp.
- Rotala spp.
- Hemianthus/Micranthemum spp.
- Lobelia cardinalis
- Staurogyne repens
- Sagittaria subulata
- Heteranthera spp.
- Eleocharis spp.
- Java/christmas/flame/willow/weeping moss
- Riccia fluitans
- Ceratopteris thalictroides
The plants in the list below are fully aquatic. Here are some plants that should be avoided for emersed setups:- Vallisneria spp.
- Blyxa japonica
- Nymphaea spp.
- Anacharis/Elodea/Egeria spp.
- Ceratophyllum spp.
- Najas spp.
- Aponogeton spp.
- Cabomba spp.
Substrate and Nutrients
To ensure that your emersed plants grow as fast and robust as possible, you need a proper substrate. There are many ways to achieve this, however I've had the most success using any of these three different methods.
The first method is to use a layer of organic, chemical-free potting soil. This will work similarly to a dirted aquarium, but there is no need for a sand or gravel cap. It works wonderfully for around a year or two, but after that point must be replaced. If not replaced, it'll begin to compact and suffocate your plants' roots, along with becoming a breeding area for anaerobic bacteria and mold. It also becomes depleted in nutrients over time, so it's best to just replace it.
The second method is to place a few pellets of Osmocote fertilizer under a cap of sand or gravel. This also works with aquarium root tabs and equivalent organic, slow-release fertilizers, but I've only tried Osmocote for this method. The pellets last about a year for smaller, lighter feeding plants such as dwarf Sagittaria, around six months for average feeders such as crypts, java fern, bolbitis, and hydrocotyle, and around three months for large, heavy feeders such as swords, Alternanthera, Pogostemon, and water sprite.
The third, and most often seen method for growing emersed plants is to use planted tank substrate such as Flourite, Stratum, or Aquasoil. This way is very successful, as you can probably imagine, but can be expensive. If you have extra planted tank substrate lying around, by all means use it, but potting soil works just as well. I've tried this method a few times, and it tends to be the longest lasting substrate. If you're planning to keep the plants in your container for more than a year, this is the best way for you.
An emersed Cryptocoryne grown in potting soil within a springtail breeding container
Humidity
Humidity is extremely important for plants transitioning from aquatic to terrestrial growth. If inadequate humidity is provided, the plants will dry out and die. A good way to provide humidity is daily misting. This keeps the leaves in contact with water, which is crucial to keep them functional for photosynthesis until the plant can grow emersed leaves.
Misting, however, is not enough to keep the plants water needs fully satisfied. Many require some form of covering over their container to hold in moisture. A piece of glass or acrylic works well, but plastic wrap will do for a few weeks. Combine the misting and covering for optimal water retention.
I also like to add a bit of water to the containers. Just enough to fill it up to about a half-inch above the substrate level. This will ensure that if your lid is ever knocked off or broken, the roots of the plant will stay hydrated in order to grow back whatever leaves were damaged.
For some plants, constant covering is essential. For others, however, exposure to air isn't a super big deal. For plants that are still adjusting to terrestrial growth, lack of humidity is a death sentence. For something like a fully established sword, it's nothing. Some people grow swords, dwarf sag, and anubias with no covering at all because they can handle lower humidity. The container should still always have a tiny bit of water in the bottom, though.
Lighting
The light needs for emersed plants are relatively undemanding. A simple LED strip will do the job, although the growth will always be faster with a better light. Even an east facing window will work. If you do use a window, make sure that it's one with little or no direct sun and plenty of indirect light. Direct sun will burn the plants. A tiny bit is ok in the morning or very late afternoon, but nothing more. I use both LED grow lights and window light to grow my plants. They grow very well like this despite the lack of particularly fancy lighting.
Common Pests
Unfortunately, Emersed plants are subject to many of the same pests as immersed plants. As this is a very humid environment, algae and snails can both still spread within these containers. The best way to prevent snail infestation is to do the same as you would with an aquarium. A bleach or peroxide dip will kill off any eggs or snails on the plant.
There is no true way to prevent algae infestation, other than proper ventilation, which will be detailed in the next section. If algae has already taken hold, you don't need to worry. Unlike in aquariums, the algae here won't grow on plant leaves and block light. As long as you keep the top of the container where light comes in free of algae, the plants will do fine. Algae also grows much more slowly out of water, so you don't have to remove it too often.
Ventilation
As mentioned in the section above, ventilation is very important for emersed plants. To avoid mold and algae growth, proper airflow is needed. There are a few ways that I've used to achieve a proper balance between humidity and air.
The first method is to simply add holes to the top. For glass, you may need a special drill bit, but acrylic and plastic are easy enough. Don't add too many holes, as this will let too much water out, but a few are fine. I would do about 3-5 holes lengthwise along the middle of a 2ft long container. Mist this around twice a week, and it should work nicely.
The second method is to break off the corner of the top. For glass and acrylic I usually don't do this, but for plastic, you can just saw the corner off. Since this is a larger hole, it means you have to mist more often. Every other day should be ok.
The third method is my least favorite. It involves using a small fan to keep the air circulating. It does provide superior circulation for the plants, but is just more complicated than necessary for most people. The plants don't do any worse with holes in the top, so unless you need to, there is no reason to use a fan. It is a good option for someone who can't mist often or has to run lots of emersed containers, as you only need one small hole in the top for this to work, but is entirely unnecessary for anyone who just has a few containers and a few extra minutes to mist.
A Bolbitis heudelotii I recently moved to my dart frog vivarium
This is the information I have gained after years of experience with emersed plants. It may seem complicated, but it can actually be a very easy and fun way to multiply your plants. Doing this can get you dozens more plants for not just cheap, but possibly free. I hope this was helpful.
(sorry this is so long)
Advertisement
