How to Keep Diseases, Mould, and Pests out of Your Grow Room

5 handy tips to keep diseases, mould, and pests out of your grow room

You think your cannabis plants would be safe when grown indoors. But no! Even in a secure grow room, cannabis plants can still be susceptible to diseases, fungi and pests. There are a few basic things you can do to minimise the chances of this though. Read on.


Tip 1. Buy strains that are most likely to resist disease and mould

Northern Lights mould-resistant cannabis

Northern Lights – a resistant strain

Due to all these years of selective inter-breeding, there are now a good few strains which have been bred to be particularly resistant to mould or disease. You can get yourself off to a good start by getting seeds of these hardy resistant strains. Northern Lights is always a favourite in this regard.

Click here to browse a good selection: Mould-resistant Seeds (


Tip 2. Use clean potting soil

Obviously, re-using the soil from a previous grow will save you money and hey, it’s recycling, right? However, soil that’s been used will have lost some of its nutrients (they’re in the previous plants you grew). Not only is this not great for your new plants, it also makes the soil more likely to hold diseases and pests.

Give your new plants the best start in life. Nourish them well. It’s cost-effective in the long-run.


Tip 3. Don’t use mulch (or anything else) around the base of your plants

While on the subject of soil, keep your top soil clean. This way, there’s nowhere for bugs and fungi to hide. Pick out dead leaves before they decay and don’t put on any mulch of any kind. Although some argue that using mulch can insulate the soil, it’s more likely to provide a perfect home for insects and mould.

You might get away with using mulch that’s completely organic, but if you do go for that, keep a close eye on what lies beneath….

white widow

White Widow – a classic indoor strain


Tip 4: Give your plants plenty of fresh air

You need to maintain a proper circulation of air in your grow room. Get a good vent fan to remove moist air.

Firstly, a well-ventilated room will be less humid and since mould loves humidity, a drier room is less likely to become mould-infested.

Secondly, the flow of air around your plants will physically stop moulds and bugs actually attaching to your plants. Both insects and mould spores will find it harder to settle on your lovely plants if there’s a bit of a breeze. You can literally blow them away.


Tip 5: Clean everything

Obviously you need to keep everything in the grow room clean to prevent disease, including your tools, to make sure they’re not contaminated with diseases or moulds from other plants. You can dip your tools in rubbing alcohol or just scrub them carefully with hot water and detergent.

You need to keep yourself clean too. This might sound a bit over-zealous, but you’d be surprised how much dodgy stuff you could be carrying on your skin or clothes. Wear clean clothes that haven’t recently been outside to enter your grow room. And wash your hands thoroughly before touching your plants. OCD is your friend here…

If you take these basic precautions to keep diseases, moulds, and pests out of your grow room, the chances are you’ll get a nice healthy crop – free from diseases, fungi and insect predations!


What are you waiting for? Get started with the best quality seeds

Not sure which seeds to go for? Browse our selection (on our sister site) of the best indoor seeds:
Top Ten Indoor Cannabis Strains


These tips are based on advice from – the UK’s top cannabis seed seller.