Keeping algae at bay in your rain barrel involves a few simple preventative measures and occasional cleaning. Here's how you can prevent algae growth:
Preventative Measures
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Block Sunlight: Algae needs sunlight to grow. An opaque (non-transparent) rain barrel is the best defense. Make sure your rain barrel is made of dark-colored, light-blocking material. If your barrel is translucent, consider painting it a dark color or placing it in a shaded area.
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Use a Screen or Filter: Install a fine mesh screen at the inlet of your rain barrel to prevent leaves, debris, and insects from entering. This organic matter can provide nutrients that algae thrive on. Regularly clean this screen.
Treatment Options
If algae appears, consider these options:
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Vinegar: Add 1 cup of white vinegar to a full rain barrel. Vinegar helps to control algae growth. The diluted vinegar is generally safe for watering most plants, but it's always a good idea to test it on a small area first.
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Bleach (Use with Caution): As a last resort, you can use a small amount of regular, unscented, liquid household bleach. Add 1/8 teaspoon of bleach per gallon of water in the rain barrel. Stir well and let it stand for a day or two before using the water. Important: Use this method sparingly, as excessive bleach can harm plants and soil. The water is then acceptable to use for non-edible plants.
- Calculation Example: A 50-gallon rain barrel would require 6.25 teaspoons (approximately 2 tablespoons) of bleach.
Regular Cleaning
- Annual Cleaning: Clean your rain barrel at least once a year. Empty the barrel completely and scrub the inside with a stiff brush and a solution of water and a mild, eco-friendly soap or vinegar. Rinse thoroughly before reuse. This helps remove any existing algae and debris that may contribute to future growth.
Summary
By blocking sunlight, filtering incoming water, using occasional treatments like vinegar or diluted bleach (carefully), and performing regular cleaning, you can effectively prevent algae growth in your rain barrel and keep your harvested rainwater clean and usable.
