Many of the plants we keep and enjoy in our aquariums will grow well in both submerged and emersed above water. Most of them need a humid environment to do so, but once adapted they will grow quickly. In fact many plants we keep in our aquariums are actually not true fully aquatic plants.
Most of these plants we keep grow part of the year underwater, but when the dry season comes along they adapt to grow alongside the waters edge. This behavior makes it possible for the plants to disperse to more areas instead of those that are dedicated to underwater full time. This type of adaptation and flexibility helps them survive where they otherwise would shrivel up and die, or drown.
Emersed growth, the form of foliage that grows above water, is usually much more sturdy than the underwater growth. The emersed plants need the extra support because they are not weightless (or buoyant rather) above the waters surface. It is usually quite obvious which is emersed grown when holding two of the same kind of plants grown in the very different conditions. The leaves of cryptocorynes and swordplants are much more tough and textured looking but often less colorful. A good many stem plants are the same way.
There are many reasons to grow plants emersed instead of below the surface of the water. Many nurseries that provide aquarium plants grow theirs emersed because they grow faster and are easier to propagate. This should be a good reason to look into emersed grown aquatic plants as well. The plants can be stored much easier without collecting all types of unsightly algae. Many aquatic plants will only flower emersed grown but there are exceptions and we will see some plants bloom underwater.
An excellent way to grow emersed aquatic plants is with an aquarium or plastic bin with a lid to retain humidity. A layer of substrate that is suitable for the plant is necessary as each plant has its own needs for its roots to thrive. One of our most common substrates however contains almost entirely Miracle Gro potting soil.
A layer of potting soil is laid in the bottom of the tank or bin and water is added to somewhere above the level of the potting mix. Some plants prefer the water table to be below the top of the potting mix, some even with it, and even yet some prefer several inches of water above the potting soil or substrate. Simply place your plants or cuttings in the substrate and provide lighting. Initially you may help them get started by misting them with a spray bottle of aged tapwater until they acclimate to the new settings.
Since the plants are no longer gaining nutrients from the water column while growing emersed they need a fertilizer they can take in through the roots. One quarter teaspoon per gallon of a balanced fertilizer such as a houseplant formula work fine for most of our plants we grow emersed. The amount of that mixture that you use will depend on how many plants you have in a container and how big that container is. Start with a teaspoon of the fertilizer mixture once a week until you get some experience with how much to use for your particular setup. After tha tyou can experiment more. Remember to let your plants recover for several days before fertilizing them.
These emersed grow plants will be in need of some lighting to help them grow. Since the lighting doesn’t have to penetrate the water column it is easier to light an emersed setup. A grow light or a shop light will work great for growing foliage. There are fluorescent tubes readily available specifically manufactured for plant growth, but there are also plenty of daylight bulbs in the 5500K to 6500K range. You want to get at least a 5500K bulbs if you can but they will grow with a lower Kelvin rating as well.
Once your plants are growing and doing well in the emersed setup you can continue to trim and trade them, growing your collection, or you can use them. Remember that many stem plants you buy are emersed plants bundled and wrapped with weighted wire. Simply snip off stem plants to your desired length and using forceps plant them in your aquarium, terrarium, or wabi kusa. Keep them moist while you work on your new aquascape to reduce stress to the plants.
Cryptocorynes are one of those plants that can melt down and do a hard reboot. They will most often come back from the rhizome after turning their leaves to mush and sloughing them away. This is so common that its called melt or crypt melt. It doesn’t mean the plant is dead, it just means that it knows conditions have changed and its not going to keep growing the other type of foliage. Keep it planted and in a few days to a couple weeks you will most likely start seeing the new growth coming from the rhizome.
Many plants do have separate forms of submerged growth and emersed growth. Once a form is taken, either submerged or emersed, the plant has to grow the new form of foliage. It doesn’t always die back, but it doesn’t always acclimate easily either. Occasionally there are some completely different colorations, growth form habits, and foliage that are markedly different.
If you like to experiment with plants give emersed growth a try and see how well you do. Its a great way to extend your plant collection and a great way to extend your hobby into other areas of aquascping. Its easy, inexpensive and fun!