health

Houseplant hacks: does fish tank water work as fertiliser?

Rather than pouring away old aquarium water, you could use it as free plant feed

Houseplant hacks: does fish tank water work as fertiliser?

TL;DR

  • Aquarium water contains nitrogen, phosphorus, and beneficial bacteria, making it a free plant feed.
  • Use water from a freshwater tank that is changed often and collected during a partial water change.
  • Allow the water to reach room temperature before using it on houseplants.
  • Aquarium water promoted healthy growth in a monstera and a peace lily over a month.
  • It is a useful supplement but does not entirely replace balanced fertilizer due to variable nutrient ratios.