Algae in hydroponics: managing strategies

If you’re one of us hydroponics enthusiasts, you know about our chief nemesis: algae growth. Algae create buildups, clogging the system and affecting the circulation of the nutrition solution. Algae in hydroponics are a pain, and all gardeners know it. But is there anything we could do? And what happens if we don’t? Why don’t we help you answer all these questions?

We’ll share with you our experience of dealing with algae in hydroponics. Hopefully, our tried and tested tools will help you tackle this issue and come out on top.

But we would like to start with some basics about algae themselves.

Worst enemy or just a neighbor?

Algae

Algae are part of a very diverse group of aquatic organisms that are capable of photosynthesis. They don’t have roots, stems, or leaves, but they resemble plants in other ways.

And here comes the root of the issue with the algae invading hydroponic systems. Their needs are the same as the needs of the plants in your hydroponics. They need water, nutrients, and sunshine to conduct photosynthesis.

That’s why algae thrive in hydroponic systems.

The following species love to call our hydroponic systems their home.

Species

Green algae are very common inhabitants of a hydroponic system. Green algae look slimy and resemble moss floating underwater.

Their bluish-green variety contains Cyanobacteria, which gives green algae a blue hue.

Brown algae have a green-brown or just brown hue, are well-adjusted to colder climates, and live predominantly in ocean waters. They have a more complex structure compared to other algae species.

Black algae are an indicator that the hydroponic system hasn’t been managed correctly, including an unbalanced pH level and poor filtration systems. They look like bluish-green-turning-black colonies of dots and blotches, and they love warm water.

We don’t wish you to have red algae in the hydroponics system. These slimy red and purple algae are the cause of the infamous red tide. They are toxic to marine fauna.

Is cohabitation possible?

A hydroponics system is a paradise for algae. They have everything they need to flourish. Water is in abundance; the sun is for their photosynthesis — of course, you set up your hydroponic and aquaponic systems in the best possible location; nutrients — the nutrient solutions are packed with them.

You created a perfect hydroponic garden and, at the same time, a perfect environment for the algae to grow. So, on the one hand, we can say that algae are an inevitable companion for hydroponic gardens.

On the other hand, that’s the neighbor you would want to control; otherwise, you’ll get your hands full with a hostile power.

Too much algae in hydroponics. The unwanted effects

In moderate amounts and a completely controlled environment, algae don’t pose a danger to the system. But in case, algae grows uncontrollably, the situation changes for the worst.

After algae spores get into a hydroponic system, they are there to stay because they have found the best habitat. Algae microscopic airborne spores are just spread everywhere by the wind, so the chance of them reaching your hydroponic or aquaponic systems is extremely high.

If you don’t pay enough attention to the algae growth, you’ll have your hands full pretty soon.

Apart from physically clogging the pipes of the hydroponic systems, algae colonies will starve the plants by feeding on their nutrient solution.

Algae also play a big role in destabilizing the pH level in hydroponics systems. During the night, algae release carbon dioxide into the system, thus causing the pH level to fall dramatically. At the same time, a dissolved oxygen level drops too, stifling the plants.

During the day, however, thanks to photosynthesis, the oxygen level leaps together with the pH. The result: pH levels are extremely volatile, and it’s harmful to the plants’ growing process.

The algae growth can also do damage to the plant roots. They coat the roots and don’t let the plant roots breathe. On top of that, algae are a medium for pathogenic fungi and toxins that are damaging to hydroponic gardening.

And last, but not least, algae decompose with a horrific smell, and trust us, you don’t want that smell anywhere close to your garden.

Cancel algae or avert them

Now we’re going to equip you with all the tools you can use to fight off algae attacks and to avert them per se.

Eliminating the threat

Conventional method

Let’s start with the traditional and effective method of killing algae and cleaning hydroponics systems.

A hydroponic system can be set up both outdoors and indoors. In the case of the latter, you need to go through an extra step and clean the growing room because algae spores are most certainly there somewhere.

So, all your hard work is not in vain, wipe all the surfaces with the following cleaning solution: 5 parts of water for 1 part of vinegar. Be thorough. And make sure you wipe the system’s air intake filters. They are very likely to contain all kinds of spores.

Now, to the system cleaning.

  1. Drainage

First, you need to get rid of the contaminated nutrient solution. If you use pumps, it will be easier. If not, drain the tank manually according to the system drain instructions.

  1. Preparing a cleaning solution

We recommend cleaning and disinfecting the system after every cycle. This way, you’ll prevent algae growth from getting out of control and disrupting the system’s organic balance.

You have 3 major options in terms of cleaning solutions.

Vinegar. This solution we recommend for organic gardeners.They won’t be able to use the other two options. 1 part vinegar and 5 parts water. Although vinegar is not a sterilizer, it’s still a decent disinfectant.

For the rest of us, there are 2 more options.

35% food-grade hydrogen peroxide. This cleaning solution will provide sterilization too.

Bleach (odorless). 1 part of bleach and 100 parts of water.

  1. Cleaning pumps, hard-to-access parts, and air stones. Getting rid of broken roots

To make sure you get rid of all algae from the pumps, keep them in the cleaning solution (it can be a bleach, vinegar, or hydrogen peroxide solution) together with a growing medium and pots for some time.

Clean the hard-to-access parts manually, taking them out and giving them individual attention. There can be parts of the plant’s root system or dead algae stuck in the system along with other waste.

Make sure you rinse all the parts thoroughly to remove all the solution from them.

  1. Scrubbing

Now you need to ensure that there are no traces of algae left in the hydroponic system. Scrub all the parts of the system with green scrubbing pads. And use the solution that you prefer. After drying the parts with a cloth, piece them back together.

  1. Sterilizing the system

This is an important stage, as here you are preventing algae growth for the longest possible period. At some point, hydroponics algae will find its way to your system, but hopefully not too soon.

Fill in the system with the chemical solution of your choice and let it work for 4-5 hours. That should be enough for the total system sterilization.

  1. Rinsing

Don’t forget this last step. After sterilizing, you must wash off the solution. After emptying the system, use fresh water to rinse the hydroponic system scrupulously. To finish it off, drain and dry the system with a clean cloth.

Unconventional ways

There are other methods to get rid of the hydroponic system algae. They are not as common as the one we’ve just described but also proved to be quite effective.

  1. Grapefruit seed extract

We love organic methods, and a grapefruit seed extract is an effective tool for hydroponics algae control. It has antiparasitic qualities and inhibits algae growth. 5 drops of the extract per gallon of water will be enough. It’s not harmful to plants.

  1. UVC light sterilization

If you sterilize the system with UV light, it will eliminate all the spores and microorganisms which is great, however, it won’t kill already-grown algae. It’s usually set up in the filtration system.

  1. Barley straw rafts

Barley straw rafts in the specific conditions of aerobic decomposition produce a substance that inhibits algae growth. This method is completely organic but slow. You have dissolved oxygen in the nutrition solution, so aerobic decomposition is possible.

Avoiding the threat

We’ve already agreed that it’s not possible to prevent algae growth. But you can control algae and prevent it to a certain extent. Here’s how you do it.

  • Try to deprive the algae of sunlight. Cover the parts of the system which can be covered, like water tanks. Paint the tanks in dark colors and use dark-colored pipes.
  • Use algaecide in the system. It is quite effective.
  • Remove the algae from the water tanks and give them a regular scrub.
  • Every 2-3 weeks change the water in the tanks.
  • Using Rockwool and LECA media proved to help too.

Conclusion

If you can’t win it, learn to control it. This wisdom works for algae too. In small and in large hydroponic systems, algae are a pain. We gave you a detailed guide, and we are confident that it will make it easier for you to control algae and make the best of the hydroponics.

Frequently asked questions

Is algae good for hydroponics?

Algae are harmless in small amounts (and inevitable too), but when unmanaged, they can become very harmful to hydroponic plants.

How do you prevent algae in hydroponics?

You can’t prevent them completely, but there are some measures you can take to control them, like using algaecide and changing the water every couple of weeks.

Why is algae a problem in hydroponics?

Algae can be harmful to plants by depriving them of nutrition and consuming dissolved oxygen. They also destabilize the pH levels of the system and are a medium for harmful microorganisms.

Is algae okay in my hydroponic herb?

A small amount is OK, but make sure you control them because if they grow too much, they can harm the plants.

Read also: How to grow hydroponic asparagus: expert advice

Alice Roberts

I want to start with brief information about myself so that we can become a little closer to each other. For many years I have been working in my specialty read more

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