It’s like aquaponics, the method of cycling water from a fish pond, tank, or aquarium, through plants to clean and strip the fish waste from the water, and putting the water back in the pond, tank or aquarium, except, you are the one doing the cycling–and you’re not bringing the water back!

Either way, you can harness the power of fish waste water even if it is a one-way trip to help power your indoor and outdoor plants for faster, stronger growth, excellent root development, and bigger, healthier leaf development.

Though leca clay substrate is a planting media that acts as a substitute for potting soil, it provides no nutrition to the plants that dig its roots into it. However, this is good news for folks looking to put their the waste water from their fish aquariums to its best use as these plants will be hungry for fertilizing.

One of the benefits of using leca clay substrate is that you can always have a little basin of water–fish waste water– sitting and waiting for use by your hungry hungry house plants. Of course, the bigger the planter or vase your plant is in, the more fish emulsion you can pour in it each go round. I point this out for the purpose of people who want to put as much of this fish waste water to use as possible.

Unfortunately, though you may have taken the time, money, and energy to pot up your beloved plants using the finest of potting soils available at your local home and garden store, plants can and will use up the nutrients in those soils eventually. This has been a reason that many people will repot their plants, replacing the old soil with the new, and possibly moving their potted plant into a larger pot.

Except for the case of your plant being root bound or your desire to otherwise update the pot of your house plant, it is not necessary to completely change the soil on your potted plants. By simply switching your watering of the plants to using the fish aquarium water instead of tap or rain water, you can properly fertilize your plants to keep them strong and growing without the added work of having to completely change out the soil.

This is because the main purpose of soil is to provide nutrition (and a well-aerated planting substrate) for your plants to grow in. Though the nutritional aspect of garden soil fades over time, that is easily refreshed by fertilizing your plant using the old fish tank water, or other water soluble fertilizer.

Because fish waste water is already, well, haha, watered down, it serves as an excellent natural fertilizer for outdoor plants as well. Though you can use your old fish aquarium water on any plant in need of a boost, it is especially helpful to target your garden, edible landscape, or food forest plants that may be struggling from lack of nutrition or over-mulching (which can cause a nitrogen deficiency that can kill your plants).

Of course, if you have more water changes to do on your aquarium than you have plants you can (safely) water them with on water change day, you can also collect old 2 liter bottles, pickle jars, and olive jars to pour the water into for later use.