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Mould in my Potting Mix: Good, Bad or Mother Nature working her magic?

Seasonal changes, increased rainfall or higher humidity can all through your carefully established plant care routine out of wack. Finding white fluffy mould on top of your potting mix might be part of it - This weeks blog runs you through what it is, what it does andif you need to even worry.

It can be a shock though - no one wants to come home and find their potting mix looking like a Swiss winter. It may seem sudden, but truth is this is a saprophytic fungi that has probably been living with your plant for some time now, and today is the day where conditions have been right for it to really take off. Good news though - Saprophytic fungi is not harmful to your plants. In fact, it exists to break down and help decompose organic materials, helping the composting process and turning organic matter into accessible nutrients for plants to consume.

Another name for these composting fungi is actinomycetes - a group of good bacteria that are an important part of decomposition and soil health. 

So we know that this is not a bad thing, but also that its not as aesthetically pleasing as a beautiful rich dark brown potting mix. 

Why is there mould now though?

Good question - something must have happened for the mould to pop up all of a sudden.

There are four good reasons for the sudden appearance of saprophytic fungi. 

  1. Excess moisture (aka overwatering)

  2. Poor aeration (aka old potting mix)

  3. Lack of sunlight

  4. Use of organic fertilisers

Excess Moisture

Mould and fungi love a nice damp soil. If your plant is being overwatered and not taking up all the moisture for itself, it will leave some sitting in the potting mix. This is perfect for any fungi within you mix to start sporing.

Poor Aeration

Actinomycetes are all about those anaerobic (no air) conditions. We've talked about the importance of aerating your soil before here, but basically better airflow = less mould. (It also means better drainage and root growth so its win win win!)

Lack of Sunlight

If you've ever grown mushrooms before, you'll know they love the dark. Poor light conditions are another thing these fungi love, so if you're battling with it  think about how much light your plant is receiving. This will also help with issue one - excess moisture. More light means more warmth meaning the potting mix will dry out quicker. 

Organic Fertilisers

If you're not on to it already, Organic Fertilisers are often packed with beneficial microbes. In fact, our Bio Pellets and Soil & Microbe Booster contain over 240 Million Microbe Colony Forming Units (CFUs) per gram. These microbes are there to speed up decomposition and help increase the uptake of nutrients for the plant. So its not uncommon for a bit of Saprophytic fungi to pop up once you start to watering them in. But remember - this is a good thing. Its a sign those products are full of life and the bacteria is starting to work its magic. 

How to get rid of the mould, though?

If you're still reading, you're probably wondering why something that can be so good has to be so damn ugly (depending on who you ask, obviously)? If you're not a fan, there are a few easy steps to take to remdy it, depending on what the cause is. 

If you're seeing mould and you haven't repotted in a while, you've probably got some old mix that is in dire need of a refresh. Grab yourself a bag of some of the good stuff and get repotting.

If you think its a water isssue, then cutting back on watering is an easy move. This is usually most common around seasonal changes when we forget to adjust despite light and temperature shifting. 

And if you know everything else is sweet as, and you've recently treated your plants to some organic fertiliser, then we suggest simply burying it in in the potting mix so you don't have to look at anything, but those microbes can still unleash their power!

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