Gardeners Glossary: Damping Off

Damping off is the term used to describe a fungal infection which will decay seedlings in their early sprouting stages causing them to die off. Usually, you will find the mould in damp soil with poor ventilation that has been left in a warm area for too long, which is the perfect environment to allow fungus to multiply.


  • A fuzzy white layer over the top of the soil (as pictured)
  • Seedlings suddenly collapsing as soon as they reach the top level
  • Discolouration of seedlings
  • Dark, rotted roots


To prevent your seedlings from damping off, you will need to make sure there is proper air circulation around your plants. You wont need to have a fan on them on all day long, but keeping the window open and allowing the breeze to blow through will keep the top layer of soil drier, while hardening your plants.


Always be sure to provide plenty of drainage opportunities to stop water from stagnating and rotting your roots. If youre having trouble with getting the water to drain, line the bottom of your pots with small pebbles which the soil will sit on and allow water to seep through.


If damping off becomes a real problem and you cant seem to find the cause after trying everything else, it may be a good idea to check the pH levels of your water supply. Alkaline water (with a pH level greater than 7) provides a much more comfortable breeding ground for fungal infections than slightly acidic water, so if its on the high end, it may be an idea to use external water sources until your plant is strong enough to be planted outdoors.


Lastly, when youre next out shopping for seeds and plants at the nursery, be sure to ask for the disease resistant ones which have developed a tolerance to fungal infections. DoLeaf is a great place to start if youre in America, but elsewhere, just asking the people that work at the nursery should give you a clue as to the plants which have been bred to handle fungus with ease. Have you had any experiences dealing with fungal soil infections and do you have any tips to share?