How to Turn Your Bath Water into Garden Fertilizer

How to Turn Your Bath Water into Garden Fertilizer

Have you ever thought about reusing your bath water to fertilize your garden? This simple practice can reduce waste while providing nutrients to your plants. As an avid gardener, I’ve been experimenting with this eco-friendly technique and want to share everything I’ve learned.

Why Turn Bath Water into Fertilizer

There are several benefits to repurposing bath water for your garden:

  • Saves water. Rather than sending gallons of water down the drain, you can redirect it to irrigate and fertilize plants. This helps conserve water, an increasingly precious resource.

  • Reduces waste. Bath water contains organic matter like dirt, skin cells, and hair. Usually this heads to water treatment plants, but it can fertilize your garden instead.

  • Provides nutrients. Substances that cleanse our bodies also contain elements that feed plants. This includes minerals from epsom salts, vitamins from soap residues, and more.

  • Saves money. You’ll spend less on commercial fertilizers and use less water for irrigation. Every drop counts!

  • Helps the environment. Diverting bath water from sewers and reusing it reduces your environmental footprint. Less waste ends up in landfills or waterways.

Clearly, repurposing bath water is beneficial on many levels. It’s one small change that adds up when we all get involved.

What’s in Bath Water that Benefits Plants

Bath water contains a number of compounds and nutrients that are useful to plants:

  • Nitrogen from dirt, dead skin cells, and hair that washes off our bodies. Nitrogen encourages leafy, green growth.

  • Phosphorus from soap and shampoo residues. Phosphorus supports root, flower, and fruit development.

  • Potassium from bath salts. Potassium is key for overall plant health and disease resistance.

  • Calcium, magnesium, and other minerals from epsom salts, bath bombs, and hard water. These strengthen cell walls and aid metabolism.

  • Vitamins like B-vitamins and Vitamin E from soap and shampoos. These promote plant processes like photosynthesis.

  • Organic matter like dirt, hair, and skin cells. This provides food for beneficial soil microbes.

The blend of nutrients in bath water makes it an excellent mild fertilizer compared to harsh chemical varieties. Plants can soak up these compounds through their roots and leaves.

Which Plants Like Bath Water Fertilizer

Most annuals, perennials, and edibles can benefit from diluted bath water:

  • Tomatoes, peppers, and eggplant
  • Leafy greens like lettuce, kale, and spinach
  • Root crops like potatoes, carrots, and onions
  • Squashes, cucumbers, and melons
  • Flowers like marigolds, zinnias, and cosmos
  • Herbs like basil, thyme, and rosemary

Avoid using bath water on plants that dislike wet foliage, like squash and tomatoes. For these, apply water directly to soil.

Acid-loving plants like rhododendrons, azaleas, and blueberries may not appreciate the alkalinity of bath water. Stick to more neutral-pH loving plants.

How to Collect Bath Water for Gardens

Collecting bath water takes a little planning but is easy to accomplish:

Supplies Needed

  • 5 gallon bucket or watering can
  • Old towels or rags
  • Funnel (optional)


  1. Plug the tub before filling. This prevents water from draining out early.

  2. Place bucket or watering can near the tub. Use a towel to avoid slipping.

  3. Fill the tub as usual. Avoid using bath oils, which can smother plant leaves.

  4. Scoop out initial rinse water. The first rinse removes most dirt and hair.

  5. Collect the remaining bath water. Carefully pour it into your bucket or can.

  6. Use the water within a few days. Don’t let it sit for long periods and get smelly.

Follow this simple routine each time you bathe. You’ll collect plenty of water for garden use.

How to Apply Bath Water to Plants

When applying bath water, follow these guidelines:

  • Use within a few days. Don’t let it sit around getting stinky.

  • Water early in the day. Avoid wet plant leaves at night, which can encourage disease.

  • Pour directly on soil for squash, tomatoes, and others that dislike damp leaves.

  • Use a watering can to sprinkle other plants, wetting soil and leaves.

  • Directly on compost to provide moisture and nutrients.

  • Dilute with regular water if foliage shows signs of stress like yellowed or curled leaves.

  • Rinse edibles like lettuce to remove any soapy residues before eating.

  • Avoid adjacent hardscape. Don’t splash bath water on patios, siding, etc. where it can leave mineral deposits.

With a little common sense, you can effectively use every drop.

Tips for Maximizing Nutrients in Bath Water

To make your bath water even more nutritious for plants:

  • Add a scoop of epsom salts while the tub fills. This boosts magnesium.

  • Use a bath bomb or bubbles. These contain minerals and vitamins.

  • Let kids play in the bath first. More dirt and skin cells means more nutrients.

  • Save water from cleaning the tub. Residual dirt left behind feeds plants.

  • Add leftover tea or coffee. The extra acidity and caffeine benefit some plants.

  • Collect rinse water in a bucket to use on compost piles.

With these additions, you can transform normal bath water into an even more powerful homegrown fertilizer.


Turning my bath water into garden fertilizer has been an easy, rewarding practice. Not only am I conserving water and reducing waste, but I’m boosting my plant growth with free nutrients. Help save water and resources by implementing this tip yourself. Once you get in the habit, it takes little effort to reap the benefits. Your garden (and the environment) will thank you!