Pennies in bird baths have become a popular DIY trick for keeping bird baths clean. The idea is that the copper in pennies helps prevent algae growth and kills bacteria. But does this penny trick really work? Let’s take a closer look at the evidence.
How Do Pennies Supposedly Keep Bird Baths Clean?
The theory behind using pennies in bird baths is that copper is a natural algaecide and antibacterial agent. When copper comes into contact with water, copper ions are released. These copper ions are thought to prevent algae and bacteria from growing.
By placing pennies in a bird bath, the copper from the pennies leaches into the water. This releases copper ions into the bird bath water, creating a natural antibacterial environment.
What Does the Science Say?
There is some scientific evidence that copper can inhibit algae growth and kill bacteria.
Studies have found that copper ions can damage bacterial cell membranes and disrupt enzyme functions in bacteria. This antibacterial effect is strongest on Gram-negative bacteria like E. coli.
Copper has also been shown to be toxic to different species of algae. The copper ions cause oxidative stress and inhibit photosynthesis in algal cells.
However, the concentration of copper needed to produce these effects is quite high. And the copper needs to be constantly released into the water at effective levels.
What About Real World Bird Baths?
When it comes to real world bird baths, the evidence for pennies making a significant difference is weak.
In most backyard bird baths, the number of pennies is far too low to release enough copper to prevent algae growth or kill bacteria.
One controlled study tested different treatments in small bird baths, including some with 10 pennies. The pennies made no difference in algae growth compared to baths with no treatment.
The copper release from a few pennies is simply not high enough to produce the antibacterial and antialgal concentrations needed.
Pros and Cons of Using Pennies in Bird Baths
Let’s weigh the potential benefits and downsides of putting pennies in bird baths.
Potential Benefits
– Pennies are inexpensive and readily available
– Adding a few pennies can’t hurt and may help marginally
– The copper release may deter some bacterial growth
– Pennies are a natural alternative to chemicals
Potential Downsides
– Not effective enough at killing algae in most cases
– Could turn the water an unpleasant green color over time
– Too many pennies may deter birds from bathing
– Occasional scrubbing still required to remove stuck-on gunk
– Need to replace pennies every few weeks or months
How Many Pennies Should You Use?
Since a few pennies are unlikely to make a major impact, how many should you use for maximum effect?
Recommendations typically range from 10 to 50 pennies per bird bath. The more pennies you use, the greater the copper concentration you’ll achieve.
However, more than 50 pennies may deter birds from using the bath. And hundreds of pennies have the potential to reach toxic copper levels.
A good rule of thumb is 2-3 pennies per inch of bird bath diameter. For a typical 15 inch bath, 30-45 pennies should strike a balance.
Make sure to evenly distribute the pennies over the bottom surface. And replace them every 4-6 weeks as the copper leaches out.
Tips for Using Pennies in Bird Baths
If you want to try the penny trick, here are some useful tips:
– Choose new, shiny pennies – older corroded ones won’t work as well.
– Scrub bath thoroughly before adding pennies to remove any existing gunk.
– Replenish pennies every 1-2 months to keep copper levels high.
– Use pennies in combination with weekly scrubbing and changing of water.
– Consider other natural antibacterial agents like grapefruit seed extract.
– If using bleach, rinse bath thoroughly before adding pennies.
What About Other Methods for Cleaning Bird Baths?
Pennies alone are often not enough to keep bird baths clean. Here are some other effective cleaning and maintenance tips:
Scrubbing
– Use a brush and non-toxic cleaner weekly to scrub off algae and grime buildup.
– baking soda or vinegar are good natural scrubbing agents.
Water Changes
– Dump and refill bath water 2-3 times per week if possible.
– More frequent changes will prevent algae and bacteria from getting established.
Bleach
– Use a 10% bleach solution monthly to kill stubborn algae and bacteria.
– Thoroughly rinse the bath after to prevent harm to birds.
Shade
– Keeping the bird bath shaded inhibits algae growth.
– Move bath or use shade structures like gazebos or trees.
Water Movement
– Add a fountain or bubbler to keep water moving.
– Motion prevents standing water and makes the bath less hospitable for algae.
Tilt
– Tilting or tipping the bath for drainage when not in use reduces stagnant water time.
The Bottom Line on Pennies
Here’s the bottom line on whether pennies effectively keep bird baths clean:
– On their own, pennies are not a silver bullet solution to bird bath cleaning. The copper release is insufficient in most cases.
– However, pennies may provide a marginal benefit when used in combination with other cleaning methods like scrubbing and water changes.
– It’s fine to try the penny trick, just don’t expect it to eliminate the need for regular maintenance. View it as a supplemental measure instead of a complete solution.
– Focus on frequent scrubbing, draining, refilling and shade to keep bird baths clean and prevent algae buildup.
Conclusion
Pennies will not magically solve all bird bath cleaning woes. But they may provide a small boost when used alongside other maintenance methods.
The key is not relying solely on pennies, but incorporating them as part of a broader cleaning regimen. With a multi-pronged approach, you can keep your bird bath clean, fresh and inviting for your feathered visitors.
Consistent scrubbing, water replacement, shading and surface disruption are still crucial for preventing the growth of algae, bacteria and other grime. But go ahead and toss some shiny pennies into the mix if you want to try harnessing their mild antibacterial power.
Every little bit helps when it comes to one of the less glamorous sides of backyard birding – keeping those baths sparkling. With the right maintenance habits, your bird bath can continue providing a safe place for birds to drink, bathe and play without becoming a swampy mess.