Houseplant enthusiasts across the UK are constantly seeking effective yet affordable ways to keep their indoor greenery thriving. One common expenditure is liquid fertiliser, essential for providing plants with vital nutrients. However, a growing number of fish tank owners are now exploring an innovative, cost-free alternative: using water from their freshwater aquariums.
During routine water changes, many litres of water, rich in nutrients and beneficial bacteria, are typically discarded. This 'waste' water, according to recent observations, contains elements such as nitrogen and phosphorus, which are crucial for plant growth. Instead of pouring it down the drain, this nutrient-laden water could be repurposed to nourish houseplants, offering a sustainable and economical solution.
For those considering this method, the process is straightforward. It is vital to only use water from a freshwater tank that undergoes frequent changes. The water should be collected during a partial water change and allowed to reach room temperature before being applied to plants. It can then be used exactly as one would apply a standard liquid feed.
Initial trials have shown promising results. For example, applying aquarium water to plants such as a Monstera and a Peace Lily over a month reportedly led to healthy growth, with the Peace Lily even producing a new leaf. While the water may initially have a slight odour, this typically dissipates quickly. The key benefit lies in its availability and the fact it costs nothing.
While aquarium water offers a valuable supplement, experts suggest it may not entirely replace a balanced commercial fertiliser. The precise nutrient ratios within fish tank water can vary significantly depending on factors like the type of fish, their diet, and how recently they were fed. Therefore, it is best viewed as an effective interim feed between more comprehensive applications of a balanced fertiliser, contributing to less waste and potential savings for UK consumers.