Contaminated Potting Soil

If you are a lover of houseplants, with an ever-growing collection, chances are you’ve encountered contaminated potting soil. It is not only annoying to deal with, it can seriously harm even the most robust leafy beauties. Types of contamination can vary from bugs to harmful microbes, all requiring differing remediation techniques.

How Does Potting Soil Become Microbially Contaminated?

Potting soil contains a combination of organic, such as steer manure and composted vegetation, and inorganic material, such as rocks and sand. This mixture is often composted at warmer temperatures with a considerable amount of moisture, breaking down the material quicker for the sake of fast production. This creates the perfect environment for bad microbes and fungus to grow. Any time you have a small portion of microbes, given the perfect conditions they can multiply at an extremely high rate.

Common strains of harmful microbes found in potting soil are norcardia, legionella, and clostridium simply as a result of the components. What initially would have been a small population of these harmful microbes, has been given the perfect conditions to grow and thrive during warm composting. High levels of legionella exposure can cause Legionnaires disease, which is a form of atypical pneumonia and symptoms include high fever, muscle pain, shortness of breath, and headaches.

How Does Potting Soil Become Contaminated With Bugs?

Bug eggs and larvae are extremely small, they would be absolutely impossible to see in a bag or container of potting soil. The eggs get mixed into potting soil either by contaminated tools or organic matter. From there the bugs finish their hatching cycle and appear, almost out of thin air, buzzing around your living room.

Getting rid of bugs in your soil and plants is extremely important. As the larvae hatch they feed on small roots and any fungus present in the plant biome, which can cause irreparable damage to your plants. They also tend to have a very small life cycle, meaning they quickly and continually recontaminate the soil by laying more eggs. They also can easily infect all of the plants in your home that are growing in soil by laying their eggs.

Types of Common Contamination Issues & How To Fix Them

If you’re struggling with any of these issues it can seem like there is no end in sight. With patience and perseverance, you can overcome serious soil contamination without reaching for toxic pesticides, getting rid of, or damaging your plants. Here’s what we recommend:

Fungus Gnats

An extremely common pest found in mass-produced soils. They are very small black flies, their larvae are impossible to see in the soil. Multiply quickly and can contaminate all plants in the home. Chances are if you have a significant amount of indoor plants it will be more difficult to get rid of fungus gnats because you will have to treat all plants.

WHAT TO DO

1. Control moisture in the soil – don’t overwater or have excessive amounts of water around your plant, gnats love warm wet soil. A great way to avoid overwatering is a method called ‘bottom watering’ which means you set your plant, pot and all, in a container of water allowing it to soak up what it needs. This removes the chance of having excessive wet soil accessible to gnats.
2. Sticky tape traps – this is an extremely simple but effective way to control the gnat population and stop adult gnats from laying eggs. Yellow sticky tape traps can be bought on small stakes to put directly into the affected plant’s soil, catch gnats buzzing around them, stopping them before they can further the gnat population. Use a few, placed strategically in different plants, to make the biggest impact.
3. Neem oil – neem oil is an effective, natural insecticide. How neem oil works are that it inhibits important brain functions of the gnats, preventing them from performing essential functions, which eventually kills them. It also has a smothering effect as well, making it a great natural option for pest control. To use mix 1.5 teaspoons neem oil, 1 teaspoon mild natural soap, and 1 liter of room temperature water. Generously spray this mixture over the infected plant, removing it from the sun to completely dry. Use this treatment weekly for the best results!

Mold

Much like your home microbiome, mold is an indicator that the delicate balance of microorganisms in your potting soil is off. The soil you’re using lacks the necessary beneficial bacteria to prevent harmful colonies from thriving. The mold typically found in potting soil appears as white, fuzzy areas on the soil surface. In addition to this being facilitated by over-watering and poor drainage, potting soil can come to you contaminated through improper composting techniques or storage. The best plan of attack is to treat it early on to prevent spreading to other plants/soil.

WHAT TO DO

1. Scrape off the top 1/2″ of soil – this is the best way to stop a mold outbreak in its path. By removing contaminated soil (be sure not to reuse the tool used to scrape the soil on any other plants before sanitizing it) you stand the best chance of getting rid of the mold issue altogether.
2. Do not overwater – mold, like fungus gnats, loves wet soil. Ensuring you have proper drainage and are not watering your plants too often will go a long way in the fight against soil mold.
3. Treat soil regularly – if the soil you are using is microbially contaminated, it would be wise to continually treat the soil to ensure you keep away mold issues. Using hydrogen peroxide on the soil surface will help kill any active mold spores, it also gives your plants a boost of oxygen which they love! Treating with Homebiotic Environmental Probiotic spray is also a great option to boost the beneficial bacteria population, offering probiotic protection against microbial imbalances.

Spider Mites

Unfortunately, this pest is extremely contagious to any plants that may be close by AND very difficult to get rid of. They can attack plants both indoors and outdoors, commonly getting into households on plants being brought inside for the winter. Often visible on the undersides of leaves, spider mites act like tiny plant vampires, piercing the leaves to suck out all the fluids. This will eventually kill the plant while the spider mite colony thrives. Most people do not realize they have a spider mite infestation until they see fine webbing all over their plant, at which point the population of mites is quite large.

WHAT TO DO

1. Remove infected leaves and wipe plant clean – the first step in the battle is to physically remove any visible spider mites from the plant. The easiest way to do this is to trim off leaves that are infested with mites and to take a wet paper towel to wipe off infested stems. This is not a sure-fire way to get rid of them but it will help decrease their numbers, making the remaining bugs easier to get rid of.
2. Beneficial predatory insects (outdoors) – if at all possible, the best way to get rid of spider mites is to introduce beneficial insects into the area. Ladybugs are sold during the summer months at farm supply stores and are a great, natural way to control spider mite populations.
3. Natural insecticide options – there are a few natural insecticide options available, many containing either citrus oil or neem oil, that not only kill spider mites but will also interrupt their reproduction cycle. This will make getting rid of the spider mites a lot shorter of a task.

References

https://www.google.com/amp/s/amp.cnn.com/cnn/2019/03/29/health/potting-mix-bacteria-partner/index.html

https://www.cdc.gov/legionella/about/index.html

https://getbusygardening.com/neem-oil-as-organic-pest-control/