Skip to Content

Why Is Algae Growing In My Aerogarden?

Hey everyone! Today, I’m going to discuss a prevalent issue in hydroponics: algae. This troublesome concern can have some adverse effects.

The primary reason algae develop in Aerogarden is due to light exposure. Most water sources already contain trace amounts of algae cells, and when they’re exposed to light, they start to proliferate. Consequently, plants, sponges, and components of the hydroponic system can get covered in a pesky green layer.

Up next, I’ll share tips on how to prevent algae growth in your Aerogarden and steps to take if you’re already dealing with it.

algae in aerogarden

How to prevent algae in Aerogarden?

The key to preventing algae growth in an Aerogarden is to prevent light from reaching it. In this section, I’ll explore various methods to achieve this. By adhering to these suggestions, you can ensure your hydroponics remain free from algae.

Use stickers

algae in aerogarden stickers

Always apply stickers to the top rim of the net pot. The Aerogarden seed pods come with stickers by default, which effectively shield the sponge surface from algae.

However, if you’re reusing the net pot, you’ll need to replace the sponge and apply a new sticker. Here, you have three choices. First, you can purchase the original Aerogarden kit, which includes these stickers.

Your second option is to buy alternative stickers. Many companies provide excellent alternatives at a significantly reduced cost.

Lastly, you can take the DIY approach to block out light. Foil is the ideal material for this. Cut a square piece of foil slightly larger than the diameter of the net pot’s top rim.

Place the foil over the top rim and fold the edges down. Then, punch a small hole for the plant. The end result should resemble the image provided above.

Change water and clean the system regularly

algae in aerogarden clean

If you don’t change the water in the Aerogarden for an extended period, it becomes a breeding ground for algae. Moreover, the algae will stick to the sides and quickly take over the entire system.

Changing out the old water for fresh water regularly can help curb algae growth. This is partly because tap water is treated and sanitized. I suggest swapping out the water every two weeks.

When changing the water, first make sure to empty out all of the old water. Then, give the whole system a good clean. Rinse it well to wash off any leftover algae clinging to the sides. Don’t forget to clean the pump filter.

Once done, fill it up with fresh water. I personally just use tap water, and it works great. The slight chlorine content in tap water not only kills bacteria but also eliminates algae cells.

Block the light

algae in aerogarden block the light

One of the most effective strategies to prevent algae growth in the Aerogarden is to prevent light from reaching the water reservoir. There are several ways to achieve this, but I’ll share two methods.

First, make sure to cover any unused pod openings. It’s a bit of a letdown that Aerogarden doesn’t provide covers for these unused holes in their hydroponic systems.

However, you can purchase these covers separately from third-party vendors. I personally use any cover that fits snugly and blocks out light.

Another approach is to wrap the grow deck with foil. You can see an example in the attached photo. A bonus to this method is that the light will reflect off the foil, providing additional illumination to the lower parts of your plants.

Read more: Best Hydroponic Garden System

How to get rid of algae in Aerogarden?

To eliminate algae from your Aerogarden, you’ll need to physically remove it. This means cleaning the bowl and deck under running water in the sink. It’s also essential to clean the pump and filter.

After cleaning, to ensure you’ve gotten rid of any remaining algae cells, you should run a disinfectant solution through the system.

What kills algae in hydroponic system?

Hydrogen peroxide is an effective way to eliminate algae in a hydroponic system. It’s widely available and easy to find.

After cleaning and setting up your hydroponic system, fill it with clean water. Then, add 3 milliliters of hydrogen peroxide for every liter of water. Ensure the system is on and the pump is operational.

Let the pump circulate for about 5-10 minutes to distribute the hydrogen peroxide throughout the system, effectively killing any lingering algae cells.

Once done, drain the water containing hydrogen peroxide. You can then refill it with fresh water and add the necessary plant nutrients.

Another alternative for tackling algae in hydroponics is chlorine bleach. Use it in the same manner as described for hydrogen peroxide, but only add 1 milliliter of chlorine bleach per liter of water.

Is algae bad for Aerogarden plant roots?

algae in aerogarden roots

Algae itself won’t harm plant roots. If there’s just a bit of algae on the roots, the plant will continue to grow unaffected.

But if the algae fully envelop the roots, it can suffocate them by depriving them of oxygen. This can cause the roots to rot and the leaves to yellow. If left unaddressed, the plant might eventually die.

How do you clean algae off Aerogarden plant roots?

  1. Remove the plant from the hydroponic system and place it in a sink.
  2. Rinse the roots under running water, removing as much algae as possible.
  3. Trim roots that are heavily coated with algae, but be cautious. Only remove up to a third of the total root system.

It’s best not to use hydrogen peroxide or chlorine bleach on the roots. Also, prevent light from reaching the reservoir to stop algae from growing back.


In summary, a little algae in the Aerogarden isn’t a major concern. Small amounts won’t cause significant damage.

Moreover, managing algae growth is straightforward. Simply change the water regularly, clean the system, and prevent light from reaching the bowl.

However, even if you follow these suggestions, it’s unrealistic to think algae will be gone for good. They might crop up now and then, but they won’t be harmful.

That’s it! Wishing you success and all the best!


Sunday 17th of March 2024

How do I clean my garden when I have large plants? I can’t remove them without damaging. Thanks

Igor Viznyy

Monday 18th of March 2024

Hi Joyce! Clean your garden without removing plants from it. If you end up with some algae in the tank or somewhere else, it's no big deal.