I am having a hard time getting rid of insects in my potting soil. My plants are droopy. I have applied a good amount of diatomaceous earth to all of them, even to the roots, but these insects don't seem to want to leave. They are white and very tiny. What can I do?

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  • Are these insects only at the roots under the soil, or walking/moving around on top of the soil, or actually on the plant foliage? Do they fly? Indoor or outdoor plants?
    – Bamboo
    Jul 19, 2015 at 18:36
  • I have not spotted any climbing the plant
    – user272671
    Jul 19, 2015 at 19:05
  • 1
    ok, so where are you seeing them then, on the soil surface? What's the potting medium you've used, was it something you bought specially for potted plants?
    – Bamboo
    Jul 19, 2015 at 19:07
  • More details please: How did you apply the diatomaceous earth? Do you know the mechanism how it kills insects? And other uses for diatomaceous earth in soil? What happened afterwards? Rain?
    – Stephie
    Jul 22, 2015 at 16:50

3 Answers 3


You still haven't said what soil you've used in the pots for these plants, but the insects you're seeing, if they're really white and don't fly, could be root aphids or simply soil mites. If the plants are obviously suffering, go and buy some sterilized potting soil (any proprietary ones will be sterilised) take the plants out of their pots, sit them in buckets of water, wash off all soil and anything else you can see that shouldn't be there without damaging the roots. Thoroughly clean and sterilize your pots, then replant using the new, sterilized soil.


Spray with diluted cider vinegar and garlic extract.

  • How dilute should the vinegar be? How much garlic extract do you add for a specific amount of diluted vinegar?
    – Niall C.
    Jul 22, 2015 at 2:14

Without a picture of the soil and the insects it is very hard to tell but the most likely identification is:

  • fungus gnats: see here and here
  • overwatering is the most common problem with house plants and wet soil encourages fungus gnats

If your plants are outside and getting too much water that would match the wilted look the leaves have. The roots are stressed or dead and cannot provide water to the leaves.

Diatomaceous earth might work but it will only catch insects on the surface, not eggs or adults underneath the soil. Read the links for other methods including the last resort method of 5 ml of bleach to one litre of water poured through the plant. Pour more water through after a few minutes. This will kill the fungus gnats but it may kill the plant. Try drying the plant out for a no risk solution.

Please read the links to answers from this site and let us know if the description and solution does the job.

  • Why do you need a picture of the soil and insect ? The larvae move too fast for me to catch them. I am assuming they are fungus gnats at this point, but the over-watering happen to be as result of recent rains. Am I Killing my potted plants by having them sit outside?
    – user272671
    Jul 21, 2015 at 14:37
  • Can I use diatomaceous earth to kill the insects?
    – user272671
    Jul 21, 2015 at 14:57
  • 1
    @user272671 a picture provides a more positive identification, there could be several insects that fit the clues you have provided
    – kevinskio
    Jul 22, 2015 at 18:00

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