Fight algae in the pond without chemicals

Algae in the pond are not just an aesthetic problem. To get rid of them, however, you shouldn’t use the chemical club. How to fight algae with natural means.

Algae are an integral part of every garden pond. They play an important role in the ecosystem, for example they produce oxygen. Under certain conditions, however, algae can multiply – and then it becomes critical for a pond. In most cases, algae can be controlled using natural means. Regular maintenance and thorough planning of the pond ensure that there is no extreme algae infestation.

Algae in the pond – causes

Algae occur in every body of water. In spring, algae bloom occurs in every pond. These are floating algae that cloud the water. After a few weeks, these algae will naturally disappear and the water will become clear again.

In addition, under certain circumstances, algae can multiply and become a problem in the pond. If algae decompose, they release nitrogen compounds, which can be dangerous for living things in the pond.

These factors favor strong algae growth:

3. Nutrients

The main cause of strong algae growth is usually a high nutrient concentration in the water. This can have different causes:

-Earth and nutrients can be flushed into the pond with rainwater

– Dead plant parts decompose in the water and release nutrients. This can also be leaves that fall into the pond.

-If fish live in the pond: fish droppings and food residues
Pond soil for pond plants with too high a nutrient content

Prevent seaweed in the pond instead of fighting it

To fight algae with long-term success, the best thing to do is to eliminate the causes. Above all, you can influence the light and nutrient concentration. You can do that:

1. When planning your pond, pay attention to a location with favorable lighting conditions, i.e. if possible no direct sunlight for hours. The pond should also not be right next to a tree, so you avoid heavy leaf fall. You should also plan the pond big enough. The larger the pond, the more stable the ecosystem.

2. Ensure adequate and diverse pond planting. The plants use up the nutrients that serve the algae as a livelihood. With the right plants, you also provide natural shading of the water surface. In this way, you extract the light from the algae in addition to nutrients. Crayfish scissors, duckweed or frog bite, for example, are well suited against algae.

Regular maintenance – remove algae from the pond

Thread algae occur in almost every pond. In itself, this is a sign of a good ecological status of the water. However, you should keep their spread at bay by regularly fishing out the thread algae. The best way to do this is with a long stick or a broomstick, with which you simply wind up the algae. You can compost the algae very well.

In addition to thread algae, you should always remove dead plant parts and leaves from the pond, for example with a landing net. So you reduce the nutrient sources for further algae infestation.

Algae in the pond – check the pH

If you cannot get rid of algae in your pond in the long term with the means mentioned, you should check the pH of the water. A high pH of 8 or higher favors algae growth.

In this case, you would have to try to lower the pH. One option is to put bags of peat in the water. However, since the peat is ecologically very problematic, you should rather choose alternatives. Oak branches that you put in the water for a long time can also have a beneficial effect on the pH value in the pond due to the tannins they contain.

6 home remedies for algae in the pond: remedies such as milk, vinegar, etc.

If certain factors in the pond are not in balance, algae can multiply very quickly and lead to serious problems in the water. As the algae infestation decomposes over time, it releases a lot of nitrogen, which can be extremely dangerous for all pond organisms. In addition, an extremely algae-covered pond area looks unsightly. Therefore, effective measures to combat and also long-term algae defense are to be taken. However, chemical antidotes should not be used in order not to pollute the environment unnecessarily. Biologically harmless home remedies for algae infestation are better suited.

Combat algae biologically

Certain types of algae occur in almost all ponds. Basically, their growth is an indication of an ecologically correct condition of the water. The so-called algae bloom occurs in spring. These are small floating algae that visibly cloud the water. Usually, these disappear naturally after a few weeks, after which the water is clear again.

However, certain weather conditions and incorrect conditions can lead to algae infestation in the water. Many pond owners then use chemical antidotes to quickly achieve the desired results. However, in the long run, these agents are harmful to both the environment and flora and fauna. For this reason, biologically harmless home remedies are recommended for this problem.

– slight cloudiness of the pond normal
– certain factors promote strong algae growth
– Too high a concentration of nutrients in the water
– direct sunlight for a long time
– permanently high outside temperatures
– Water that is too warm also promotes growth
– Pollutants in the water, such as phosphate and nitrate
– Rainfalls often wash soil and plant remains into the water
– excessive colonization by fish
– Fish droppings and feed residues cause nutrient enrichment
– Garden soil is not suitable because the nutrient content is too high
special pond soil ideal for aquatic plants

1. Remove mechanically

If you regularly maintain the pond and create it logically, you will normally not have any problems with an overgrowth of algae. The spread of algae can be kept in check by mechanically removing them from the water. Dead plant residues must also be removed, as these decompose in the water and thus release too many nutrients.

However, it should be borne in mind that thread algae in particular offer important protection for many small animals. For this reason, the animals should be given an opportunity to crawl back into the water. Therefore, do not place the removed plants too far from the pond area for a while and only then completely remove them.

– Problems mainly cause cloudy and filamentous algae
– very long and form thin threads
– Remove algae growth with a long branch, broomstick or stick
– just wind up and take out
– Alternatively, carefully fish with a net
– Do not damage other aquatic plants
– Collect dead plant parts and leaf remnants promptly
– this is how nutrient sources for algae infestation can be reduced
– then dispose of on compost heap

2. Regulate the pH

If there is often a very strong algae infestation in the garden pond, an incorrect pH value can be to blame. Therefore, this value should be checked regularly so that prompt regulatory measures can be taken if necessary. Too high a pH value favors algae growth in the long term, so the pond owner should intervene.

However, it should be borne in mind that the pH value is lower in the morning than in the evening when it rises due to external influences. This change is normal and a sign that the pond environment is working and the water is relatively clear. Aquatic plants can grow well in this environment.

– Measure the pH value with a test strip or a special device
– neutral pH is 7
– ideal pH value for ponds between 6.8 and 8.2
– higher values ​​favor the algae attack
– As a countermeasure, put jute bags with peat in the water
– firmly connect and attach to the edge of the pond
– good is floating position in the water
– continue to measure value regularly
– If necessary, replace the peat in the bag after 3-4 weeks
– Alternatively, lay the oak branch on the ground longer
– Oak bark contains tannins to lower pH
– Remove the branch before it decomposes

3. Install water pump & filter

To effectively prevent algae in the long term, it makes sense to install a water pump in the pond landscape. In this way, the continuous exchange of water can contain algae and, in the ideal case, even prevent them altogether. Since most algae species prefer calm and warm waters, the movement and cooling of the pond water is helpful in the defense against algae.

It is also advisable to install filter systems, especially in ponds with many fish. The installation of the pumps and filters depends on the pond volume; detailed information can be found in the operating instructions for the respective device.

– Water pump keeps pond water in constant motion
– disrupts algae growth in the long run
– Install the pump in an open place without aquatic plants
– Alternatively, attach fountains, fountains and water features
– circulate the water, bring fresh oxygen
– besides, the pond water cools down significantly
– Additional filters clean water, enrich it with oxygen
– Pond clarifier with UVC light is also helpful
– Ultraviolet light inhibits algae growth and fights germs

4. Shading

A very sunny location of the pond promotes algae infestation in the long term. Therefore, the correct orientation of the water should be considered before mooring, so that it does not lie in the blazing midday heat all summer. Alternatively, pond owners can use tools to provide more shade during the warm months. In addition, certain aquatic plants offer a welcome shade due to their growth habit.

– Shadow prevents algae growth
– settle broadly growing aquatic plants
– form a kind of roof
– Create pond islands to create shadows
– Stretch the awning over the pond area
– Ideally create the pond in partial shade
– but not directly under deciduous trees

5. Aquatic plants & animals

Above all, a lot of phosphate and nitrate is required for algae growth, these substances are also used by other aquatic plants. In addition, the correct planting ensures sufficient oxygen and sections with shade. Underwater plants and floating plants not only consume nutrients that are otherwise available to algae growth, but also clarify the pond water.

In addition, the pond with a beautiful placement of the plants looks more appealing. However, too much nutrient-rich soil must not get into the pond when planting. A balanced counterweight to the growth of algae is also created by the targeted settlement of aquatic animals, which mainly feed on filamentous and cloudy algae.

– Provide sufficient aquatic plants as competition
– Purple loosestrife, water hyacinth and iris are ideal
– Growing in the riparian zone Small cattail, arrow herb and water bulrush
– Plants with large floating leaves are suitable for shading
– this includes frog bite, lotus, sea jug and water lily
– Water hose and water pest have a cleaning effect
– use only special soil for aquatic plants
– Water snails act as a greedy antidote
– Shrimp also reduce algae infestation
– too many fish contaminate the pond water
– Adjust the fish population to the pond size

Tip: When feeding the fish, there must not be any remains of the fish feed in the pond. Therefore, only give as much food as the fish can eat on that day.

6. Milk & vinegar

Some pond owners recommend milk and vinegar as a home remedy for removing algae, as acid can kill certain types of algae. However, the effect of milk against algae has not been proven in practice. In addition to lactic acids, milk also contains large amounts of nutrient-rich fats, proteins and milk sugar. In addition, vinegar can severely affect the biological balance and water quality of the pond.

– Milk rather unsuitable for algae defense
– leads to longer lasting turbidity in the pond water
– Apple cider vinegar has also spread as an antidote
– pH can be significantly reduced with acid
– proceed carefully, keep the mixing ratio of 1: 2500
– Pure citric acid is much more neutral in taste

Note: Most scientists do not recommend the use of the home remedies milk and vinegar, since the rapid raising or lowering of the pH value with acidic agents places extreme stress on the pond inhabitants.

How is pond size related to algae growth?

When planning, the pond size must always be taken into account in order to rule out excessive algae formation right from the start. If the pond is large enough for flora and fauna, the water does not heat up too quickly and contains enough oxygen.

How can a biological balance be achieved in the pond?

If the pond is laid out in different stages, the growth of the algae is made considerably more difficult. These include shallow water, swamp zone and deep water, in which suitable aquatic plants can be found.

Here is an overview of what you can do against algae in the garden pond:

Fight filamentous algae in the pond

Pond owners are particularly worried about the larger thread algae. If they multiply rapidly, they cause the water in the pond to become completely cloudy. After this so-called algal bloom, the plants die and sink to the bottom of the pond. Through intensive decomposition processes, the oxygen concentration in the pond water sometimes drops so much that the fish suffocate and the water tips over.

Where do the algae come from?

There is a wide variety of algae in every pond. As long as the nutrient concentration in the water is normal, they live in peaceful coexistence with other plants and fish. But if the phosphate content rises to over 0.035 milligrams per liter, their living conditions improve. If the water temperatures and solar radiation then rise, they multiply explosively – this leads to the so-called algal bloom.

Phosphate and other nutrients get into the garden pond in a variety of ways. The most common source of phosphate are fish faeces and excess feed, which sink to the bottom of the pond and break down into their components there. In addition, lawn fertilizers or nutrient-rich garden soil are often flushed into the pond during heavy rainfall. The leaves that enter the water in autumn also contain small amounts of phosphate and other nutrients that promote algae growth.

Withdraw the nutrients from the garden pond

Not only the algae need phosphate, nitrate and other nutrients to grow, but also the aquatic plants. The more plants live in your pond, the faster the nutrients are bound by plant growth. In order to remove them from the water’s nutrient cycle, you have to cut back the water plants vigorously from time to time. You can then dispose of the clippings on the compost.

Regular fishing of the algae also reduces the nutrients in the pond. Like the aquatic plants, the algae can be composted very well. You can also lower the phosphate content of the pond water with mineral binders (phosphate binders). The nutrients are bound by chemical processes so that they cannot be absorbed by the algae or the plants.

You remove most of the nutrients from the water with a renovation. Remove the so-called mulch layer from fish faeces and decayed plants and replace the old pond soil with a new, nutrient-poor substrate. All plants are vigorously cut back, divided and then placed in new, nutrient-poor pond soil or without substrate in special plant baskets or embankment mats.

Tips for the pond system

To keep the pond water always clear, you must eliminate all sources of phosphate. The course for this is already set when the pond is created. The water looks most natural when it lies in a depression – but this carries the risk that garden soil and fertilizer can be washed into the pond. You should therefore choose a slightly higher place or surround the water with a 60-centimeter deep drainage ditch, which you fill with coarse-grained building sand.

The light conditions do not affect the phosphate content in the pond water, but sunlight promotes algae growth. Therefore, choose a location that is at least a third in the shade. The amount of water and depth of water also play a role. Rule of thumb: The smaller and shallower the garden pond, the more common are algae problems.

Use nutrient-poor sand as pond soil, and as little of it as possible. You should only use tested tap water as pond water, because many water suppliers enrich the drinking water with up to five milligrams of phosphate per liter in order to reduce corrosion in the pipes. The waterworks often publish their water analyzes on the Internet or send you the relevant documents on request. If the tap water contains too much phosphate, you should treat it with phosphate binder. Groundwater is generally low in phosphates and is therefore generally more suitable. Rainwater is optimal because it is free of minerals. Few hobby gardeners have the corresponding amount available.

Proper care for an algae-free pond

Even in clear garden ponds, nutrient-rich deposits form over time. You can remove these with a special pond sludge sucker. In addition, it is best to cover smaller ponds in autumn with a net so that no leaves fall into the water. In order to remove floating foreign bodies such as pollen or the like from the pond surface, there are also so-called skimmers that suck the water off the surface and guide it into a filter system. Under certain conditions, pond mussels can also be used as natural water filters.

Problem case fish pond

The excretions of fish, newts and other aquatic animals naturally also contain phosphate. This is not a problem as long as the animals have to live from what they can find in the pond for food. However, if you regularly provide them with fish food, additional nutrients get into the pond from the outside. There are two ways to prevent a fish pond from toppling over: either you use so few fish that you don’t have to feed it, or you install a good filter system that removes algae and excess nutrients from the pond. Large fish such as the magnificent Japanese Koi carp in particular cannot be managed without powerful technology.

Thank you for visiting our site, take a look around our site, we have many other interesting articles about the garden.

Did you like this article?
Please leave us a comment.
You can also share the article, for example on social media.

Recent Posts