How Borax Kills Mold

You hear a lot about how to kill mold, or how to remove mold.  There are debates about whether you should use a biocide or some natural alternative such as vinegar or grape seed extract.  One thing that really helps to know, however, is how something kills or removes mold.

Now borax has a really cool name, maybe because it sounds really mean like anthrax, or Clorox, or maybe just because it has the phonic ‘ax’ in it.  At any rate, borax is interesting because it is a naturally occurring substance, and in addition to its mold-fighting powers, it is also used in making glass and ceramics.  The key superpower of borax, when it comes to fighting mold, is it’s extreme pH level.  Borax is found in very alkaline (basic) mineral deposits, and carries a pH level of about 9.3, which on a scale of 1 to 14, makes it extreme enough to be effective, yet not so extreme that it becomes harmful to humans.

You see, just like you and me, mold thrives in an environment where it feels comfortable.  For most types of mold, they like to live in an environment where the ph is somewhere between 3 and 7, which is more on the acidic side (a pH of 7 is considered neutral).  Some molds even like to live in pH environments below 3!   Enter borax, the alkaline archenemy of mold.  When you apply a borax solution to mold, it turns its environment into hostile territory.  It’s like taking a shade-loving, water sucking fern from Florida, and transplanting it into Death Valley, California, where it is extremely hot, dry, and no shade.  The plant cannot survive in such environment, so it shrivels up and dies.  And so it is with mold when you apply a borax solution.

So how do you use borax when removing mold?  Below is a quick reference guide for you to use.  Borax can be purchased at any grocery store, and it is relatively inexpensive.   You can safely use borax on any surface.  If, for some reason, you are unsure of what it might do to a bathroom sink, or a piece of clothing, simply test it on a small area first.   Borax is commonly used in laundry detergents.

How to kill mold with Borax

Recipe: Combine 1 cup of borax to 1 gallon of water. (1 to 16 ratio of borax to water)

Application:  Apply solution to the moldy area, be careful not to use too much on a porous material, like unfinished wood or drywall.  These materials absorb water, which will feed the mold by keeping it moist. Scrub the area with a rag or somewhat abrasive material until mold is removed.  Wipe area clean and dry the area.  You can lightly rinse the area, and lightly apply the solution again, but there is no need to completely rinse it off because borax inhibits any new mold from growing.  That’s it!

Cautions: Don’t eat it, otherwise it’s pretty safe.

So there you have it.  Not only do you know how to fight mold with borax, you now know how it wins!