Why You Should Save Your Cooking Water for Your House Plants

I am typically not good at caring for house plants. I currently have three indoor plants, all of which are “alive,” but they are not exactly thriving. Perhaps it’s the low light levels in the Pacific Northwest (I hear there are lamps for this), or my sporadic watering schedule. Or perhaps my plants are not getting the nutrients they need to live their best life on my windowsill.

According to Kara Nesvig at The Kitchn, who originally found this tip at East River Nursery, a little cooking water may be the just the thing my leafy children need. The cooled, leftover blanching or boiling liquid contains nutrients that leach out of your food during the cooking process, and depending on what you’re having for dinner, you could end up supplying your plants with some much appreciated phosphorus, nitrogen, and calcium:

When you boil your food such as pasta, vegetables, eggs, or potatoes, many of the micronutrients such as phosphorus, nitrogen, and calcium are boiled off into the water. Therefore, after you have let the water cool down, not only will you provide your plants with a nice drink, the plants also get a bit of much needed fertilizer from the nutrients within the water.

Even if you are not extracting plant food-levels of nitrogen from your whatever it was you made for dinner, every little bit helps, and repurposing cooking water this way cuts down on water waste while saving you a little bit of money. (Depending on how many plants you have, this could be a medium amount of money.)

Just make sure to completely cool your water before dousing your plants with it, of course. You’ve probably seen what boiling water can do to spinach, so just imagine what it would do to your begonia.