Asked on Jun 27, 2018

How can I rid the weeds underneath my deck?

We recently moved into a very nice ranch; there is a large deck out from the kitchen. My issue is that there are so many weeds growing underneath the deck, and bugs, bugs, bugs! There are spaces between the flooring of the deck, so I am wondering what I could pour between the flooring to rid the area of both..? Or, spray from below, without crawling under there? I've heard of coffee beans deterring bugs (and varmints), but am unsure if this would work. Any suggestions? Thank you in advance!

  6 answers
  • Vinegar. Spray with vinegar, it will kill the weeds and whatever is lurking under there. Needs to be reapplied periodically, but vinegar is cheap.

  • 17335038 17335038 on Jun 27, 2018

    You can spray a weed killer that will temporarily kill the portion of the weeds growing above ground, but unless you kill the roots, they will continue to surface.

    The most permanent solution to the under-the-deck problem is to first kill the roots. Only Round-Up is able to go down into the soil and penetrate through the roots to stop them from growing.

    - After spraying Round-Up on the whole area, cover with weed barrier landscaping fabric. The thicker the quality, and the more overlapping of the pieces, the more efficient it will be at restraining new weeds from either growing up, or embedding themselves to take growth.

    - Anchor the fabric down with thick layer of mulch to prevent it from blowing in the wind. Or anchor the overlapping and edging portions with landscaping blocks or bricks.

    Bugs will always continue to congregate and multiply under the deck area as it is dark, lacking airflow, and usually damp. (think - dungeon)

    You may want to consider making it more attractive by completely enclosing it with lattice or similar more permanent material, or to concrete the ground surface, which would make it easier to hose clean.


  • Redcatcec Redcatcec on Jun 27, 2018

    Hi Patricia,

    If you use a product such as Roundup, keep in mind this is poison and it will be going into the weeds and their roots, as they die and breakdown, this poison is then washed into the soil by rain, water runoff, deck washing, etc. The poison then enters the drinking water that is in the aquifers in the earth and goes to the rivers, streams, and reservoirs. Eventually everyone is sharing the Roundup. Vinegar is much safer.

  • Janet Pizaro Janet Pizaro on Jun 27, 2018

    make a solution of white vinegar and waterer dab of salt and a dab of soap into a spray bottle

    • Patricia Cucchiara Patricia Cucchiara on Jun 29, 2018

      Thank you very much!! I was thinking vinegar, but unsure if it would do anything but make the deck smell like pickles!! I will try your solution! Hopefully, the bugs will be gone!

  • Ian Ian on Oct 19, 2022

    If weeds grow above an existing decking will roumdup kill them

  • Mogie Mogie on Nov 05, 2022

    I know that peppermint essentail oil keeps the bugs away. If you have any old carpet laying around that would help smother the weeds.