Buzz
Recycling water from showers, baths, or the kitchen for your garden might seem like a smart idea. After all, it’s free water, and you might assume any residues in it could benefit your plants. While the logic seems sound—water is precious, so reuse it—this approach overlooks a critical gardening principle: Avoid reusing water if it contains anything other than pure water.
For example, leftover cooking water often contains salt, which is harmful to your garden. Salt disrupts the soil’s balance, preventing plants from absorbing water effectively. Essentially, you’d be doing the opposite of what you intend. Salt is sometimes used to kill unwanted plants. Similarly, if the water contains citrus, it can alter the soil’s pH, deter earthworms, and even burn plants due to its acidity. Onions in the water can have similar negative effects.
As for shower or bathwater, it typically contains soap and shampoo residues. While soap isn’t always harmful—it can even act as a pest deterrent for certain plants, like roses infested with aphids—the concentration must be precise. Exceeding a 2% soap-to-water ratio can damage plants. The type of soap matters too; mild dish soap is usually safe, but body wash or shampoo may contain ingredients toxic to plants or disrupt the soil’s pH balance, which most plants require to thrive.
Be mindful of microplastics found in certain body scrubs and shampoos, as they can end up in your soil. If you have an outdoor shower that drains directly into the ground, pay close attention to the products you use. (As a side note, reusing mop water in your garden is highly discouraged—the cleaning agents are far too strong.)
While it’s important to avoid unnecessary waste, there are safe ways to repurpose water for your garden. Rainwater is an excellent choice, whether collected in open containers or stored in a reservoir. Additionally, if your shower or bath products are simple, free of salt, preservatives, or microplastics, the water can safely be used in your garden.
