Why does mould form?

Unfortunately the ideal growing conditions for mushrooms are also inviting to other fungi, including moulds - yuck!

If there's any area on the kit that has exposed substrate (if the white mycelium isn't really strong in that area) it could become susceptible to mould. 

Patchy mycelium can be caused by damage to the mycelium either during transit or on opening, from heat damage, over-watering or from storing the kit for too long. 


How to avoid mould issues

For the vast majority of grow kits mould will never be a problem for you but here are a few tips to avoid it.

1. Avoid warm humid weather

Mould loves warm humid weather. Ideal conditions for mould are between 25-30 degrees. If you're experiencing temperatures above 25 degrees and high humidity it is more likely you could experience mould issues. If the area you live in is prone to these conditions or you know you have trouble with mould in certain areas of your home, avoid growing mushrooms during this time or place your kit somewhere with good ventilation and cooler temperatures.

Mushrooms grow ideally between 16-20 degrees.  

2. Avoid soils and plants

Many moulds are present in all soils. Indoor plants, potting mix, and garden areas could be releasing mould spores into the air around them so don't place your kit near areas with soil.

3. Clean your knife or cutting implement 

Before cutting open your mushroom kit make sure to give your knife, scissors or cutting implement a really good clean with hot soapy water. Ideally you could wipe the knife down with some rubbing alcohol (isopropyl alcohol). But don't stress too much, hot soapy water will do the job!

4. Avoid touching the substrate and plastic with your fingers

Want to know something gross?! Your skin, fingers and hands are home to hundreds of microbial lifeforms just hanging out, including mould spores! Give your hands a good wash before handling your kit or avoid touching the substrate and plastic altogether to avoid transferring any potential contaminants onto the surface of the substrate. 

5. Avoid over-watering

You don't need to keep your kit constantly wet. Over-watering can drown the mycelium and create patchy mycelium. As long as you can see condensation on the plastic flaps, your kit is getting enough moisture. The kit already has a high moisture content for the mushrooms to grow, the misting is to create humidity to encourage the mushrooms to grow, not to provide them with water. 

6. Open your kit as soon as you receive it

Storing your kit for too long can effect the vitality of the mushroom mycelium. For best results open your kit and start growing once you've received it. 


If your kit has developed some mould you can reference our article How to identify contamination in mushroom growing for advice on what to do.

If you're still unsure about your kit or need some extra assistance please send us a message and we'll get back to you shortly.