Mold And Algae On Your Aerogarden Sponges & Other Growing Substrates

Ew, I Found Mold On My Seeds And Aerogarden Sponges! What Does This Mean?

We get it; the presence of white fuzzy stuff is rarely a pleasant surprise for gardeners and plant owners. But before you go throwing everything out and starting over, allow us to present the case FOR it. Although often misunderstood, mold in hydroponic systems such as aerogardens offer some surprising benefits to your plant’s health and may not actually be as harmful as it might seem at first. 

Mold has been known to occur on AeroGarden compatible grow sponges (most common), and occasionally in our own Bottle Garden kits, which use a similar type of grow sponge. What all of these products have in common is that they all include some sort of growing medium (or “Smart Soil”) that is used for germinating seeds. 

This growing medium is made from materials that include coco coir, peat moss and sometimes composted fir bark. Often the same habitats suitable for plant growth are also suitable for fungus and algal growth, and this is just a part of nature.

What Exactly Is Garden Mold?

‘Mold’ is part of the fungus family, and consists of millions of small organisms that can appear white, black, orange, green or purple. Mold exists everywhere – indoors and out – and whether you realize it or not you are encountering it every single day of your life. 

The type of mold that you are most likely to encounter on (or in) indoor gardening products or hydroponic systems like your aerogarden is called Trichoderma

Trichoderma is actually an incredibly beneficial ally to your garden. It reduces Pythium, Fusarium, and Rhizoctonia, some of the most common plant parasites. Some gardeners will actually deliberately inoculate, or introduce, Trichoderma due to the slew of benefits it offers – especially during the root development stages of the plant’s life. However, we know this may not immediately alleviate concerns around what can appear to be a fuzzy white takeover of your precious seedlings.

How Can You Prevent Mold?

Understanding how to prevent mold on your aerogarden sponges is as simple as understanding what mold needs to grow and thrive. Mold, in general, tends to thrive in environments that are damp and warm – including packages of hydroponic grow sponges that are shipped during summer months in closed containers (i.e. our products, and all other Aerogarden compatible grow sponges). 

If you want to prevent the mold in your aerogarden, then we recommend either reducing temperatures, moisture levels, or both. Prior to packaging, we air-dry our plugs on large racks in order to reduce the chances of a Trichoderma bloom (not because it’s bad, but because it tends to induce a 1-star review), and if you don’t like the look of it we recommend you store your sponges in a cool dry place.

How Can You Start With Mold Removal In Your Hydroponic System?

The easiest way to start with mold removal in your hydroponic system is to physically agitate it. If the hydroponic grow sponges are still in a bag, you can just mix them up or shake the bag. If that’s not an option, simply brushing off any mold that you see will do the same thing. 

The benefit of this approach is that you will remove the visible signs of the mold on the surface of your plug while retaining the root-protecting beneficial fungi within the plugs themselves. Win-win.

Is Putting Hydrogen Peroxide On Your Aerogarden Sponges Safe?

Some retailers and distributors of similar products treat their products with hydrogen peroxide. Technically putting diluted hydrogen peroxide on your aerogarden sponges is safe, and it is effective at killing fungi like mold (both good and bad), as well as reducing the chances of algae blooming (although this is more related to keeping your Aerogarden clean in general). 

Since you are going to be eating food grown in these plugs, we prefer to keep the Trichoderma in and the chemicals out. But if you would like to treat your own moldy plugs with hydrogen peroxide then go for it – this is cheap and readily available and can be applied with a spray gun or mister, just be sure to keep your hydrogen peroxide concentration below 4%.

It’s Not Mold, It’s Algae On Your Coco Coir Aerogarden Sponges 

What Is Algae & How Is It Different From Mold?

Algae is a type of plant, not a fungus. Algae is a simple, non-flowering, and typically aquatic plant from a large family that includes seaweeds and many single-celled organisms. Algae contains chlorophyll but lacks the true stems, roots, leaves, and vascular tissue we associate with plants.

Is Algae Bad for Plants or your Aerogarden Sponges?

Algae is normal and not usually harmful for most hydroponic systems, especially if it’s present in a low amount. Most of the time, you can wait until harvesting your crop before you treat your hydroponic system for algae growth, or you can also try the approach that we discuss below.

How Can You Prevent Algae In Coco Coir Aerogarden Sponges?

The same conditions that make our grow sponges a great place for seed germination and plant growth also make them a great environment for algae. Algae requires the same inputs that plants needto thrive, including 

  1. light, 
  2. water and 
  3. nutrients 

When all three are present, the environment is ripe for both plants and algae.

In order to prevent algae in your hydroponic grow sponges, we need to remove one of these three inputs. Since we’re talking about hydroponics taking out the water and nutrients isn’t really an option. 

The approach we recommend to prevent algae in your aerogarden or any other hydroponic system or growing media therefore, is to remove the light. This can be achieved by placing some sort of light-shield around the base or stem of the plant – which could be as simple as a round piece of paper or piece of cardboard with a hole in the middle for the stem of the plant to grow through. This is a tried and true method for reducing unwanted growth, and one embraced by Aerogarden themselves, as you may have noticed the paper light covering on brand-name seed pod kits.

Regular cleaning of your hydroponic unit will also go a long way towards eliminating the chance of algal growth. This should be done in between harvesting and planting. Soap and warm water may be sufficient to clean your water reservoir, but if you have a particularly nasty algae infestation, you should also clean with isopropyl alcohol (just be sure to rinse it all out before starting up your garden again).

If you’re looking for a budget and eco-friendly replacement for your AeroGarden pods, try out our AeroGarden Compatible Grow Sponges which work quite well when paired with our dwarf seed varieties. And if all this mold-talk has got you second-guessing – don’t worry, we won’t leave your plants out to rot! We offer a Green Thumb Guarantee where you can always get a replacement or refund for your purchased product.

Leave a comment

Please note, comments must be approved before they are published