Boric Acid - Insecticide - Woodworm - Wet & Dry Rot


SKU: RD11397

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Technical grade

Boric acid, also called boracic acid or orthoboric acid is a mild acid often used as an insecticide, flame retardant, in nuclear power plants to control the fission rate of uranium and as a precursor of other chemical compounds. It exists in the form of colourless crystals or a white powder and dissolves in water. It has the Chemical formula H3BO3, sometimes written B(OH)3. When occurring as a mineral, it is called sassolite.

In the jewellery industry, boric acid is often used in combination with denatured alcohol to reduce surface oxidation and fire scale from forming on metals during annealing and soldering operations.

It is also used in the manufacturing of remming mass, a fine silica-containing powder used for producing induction furnace linings and ceramics.

Please Note: This product has been reclassified by the ECHA as Reprotoxic Category 2 and as such is not available to the general public. This change does not affect availability for business users, companies or scientific research.

PLEASE NOTE: This product is not for human or animal consumption.


BORIC ACID as an insecticide

Boric Acid Powder is often used as a relatively nontoxic insecticide, for killing cockroaches, termites, ants, fleas and many other insects. It can be used directly in powdered form for fleas and cockroaches. Sprinkle powder finely on carpets, floors etc. For carpets work into the carpet with a brush to ensure it gets to the bottom of the pile. the fleas will pick up the fine powder on their bodies which will kill them.

Boric acid can be mixed with sugar or grape jelly for ants. It is also a component of many commercial insecticides. In this use, especially in the case of cockroaches, the boric acid in the form of a powder is applied to areas frequented by the insects. As an insecticide, boric acids mechanism of action is not fully known- it may involve destruction of the foregut lining of cockroaches, possibly causing starvation. Boric Acid Powder for this use in residential apartments is sold commercially in urban areas afflicted with cockroaches. (See below for more details)

Click here - A study on the effectiveness of Boric Acid Powder against Cockroaches

Boric Acid To Kill Wasps: Boric acid is an excellent way to kill a hive of wasps. If you can sprinkle the powder into the nest it will be the most effective. If not sprinkle as close as possible and they will carry it in. Please make sure that you use Boric Acid and not Borax and also make sure that it is the POWDER version of Boric acid and not the more common granular form.

You can kill all flying insects with a solution of boric acid in water. Dissolve 100g in 1 litre of warm/hot water, allow to cool and put in a spray bottle.

How to use Boric Acid to kill ants in the garden.

Boric acid has been a favorite weapon against ants and roaches for more than a century, and is one of the most effective cockroach control agents ever developed, provided that it is used correctly. CAUTION: It should be kept away from children and pets.

But the best solution is to put out baited traps that contain a low dose of boric acid. The ants take the bait back to the nest, where the slow acting poison is toxic to some insects and can kill the entire colony.  Here's a detailed description of a pet-safe, ant-deadly trap design from the BIRC:

1.    Mix together: 3 cups water; 1 cup sugar; and four teaspoons of boric acid. DO NOT USE MORE BORIC ACID THAN THIS! A higher dose would kill the ants immediately; and you need them to live long enough to get the bait back to the main colony.  If you see a lot of dead ants around your traps, you used too much!
2.    Get six jars with tight fitting screw-cap lids; punch some holes in the lids with a Phillips head screwdriver. Loosely pack the jars about half full with cotton balls or batting, then saturate the cotton with your boric acid sugar water.
3.    Screw the lids on tight and draw 'skull and crossbones' on the jar, just to be safe.
4.    Leave the jars out where you see ants. Most importantly, do NOT kill any ants from here on in as you have to let them travel to and from the jars safely so they can take the bait back to the colony.
5.    Not all ants are sugar-suckers; some species prefer protein. If your ants aren't attracted to the sugary bait, make a new batch using cat or dog food. If you have carpenter ants, use wet, rotting wood. Experiment with the boric acid levels until you get the dose right.

Repellent plants
Catnip, pennyroyal, peppermint, sage, and spearmint. Tansy which is often recommended as an ant repellant may only work on sugar type ants. These are the ones that you see on peonies and marching into the kitchen.

Here is something interesting: it is said if you take a shovelful of ants from one hill or nest and put it in another ant hill then take a shovelful from that hill and put it where you took the first one the ants will then wage war on one another and do themselves in!

Ants will not walk through a line of talcum powder or chalk dust. Diatomaceous earth may also be used as a barrier in and out of the household.


How to use Boric Acid powder to kill fleas on carpets

Boric acid is a wonderful tool for controlling fleas in homes, especially on carpets where they tend to live and lay their eggs. It is effective in extremely small amounts and retains its potency almost indefinitely provided the deposit remains dry. Boric acid is deadly to fleas, but is low in toxicity to people, pets and other non target animals. It is also odourless and contains no volatile solvents. In humans, boric acid is only slightly more toxic than table salt but care must always be taken when using around pets and children.

Fleas succumb to boric acid when they crawl over treated areas. Boric acid powder kills fleas by acting as a desiccant causing severe dehydration to them and ensuring death. In order to eliminate the fleas it is important to treat all areas by sprinkling the powder over the surfaces.

***How to make an applicator for using boric acid***

Take an old Pringles container or similar which has a detachable plastic lid. It is important to place stick a label on the outside of the container and write clearly that it contains Boric Acid so as there is no chance of it being misused at a later date. Put a few pebbles into the container (these help to prevent the powder caking when it is stored away and also helps when applying). Now fill the container up to about 2/3 full with the boric acid powder. Carefully, using a knitting needle or similar pointed tool pierce the plastic lid of the container 20 or 30 times to form a series of holes through which the boric acid can pass.

Alternatively just buy a shaker as for instance used for castor sugar but make sure that you label it for the boric acid and keep it away from food stuffs and out of reach of children.

***Where to apply the boric acid***

Where the powder is applied is just as important as how it's applied. Fleas prefer to live in carpets, fabrics, upholstery, bedding etc. All areas can be treated with boric acid powder but care should be taken with coloured fabrics to prevent possible discolouration. If unsure pre-test an inconspicuous area first. Remember to apply under furniture.

NEVER apply boric acid onto countertops or other exposed surfaces, especially those used to prepare food.

***How to apply boric acid to kill fleas***

Before applying boric acid it is advisable to vacuum the carpets, upholstery etc first. Dispose of the vacuum bag into the bin as many of the fleas will been lifted. Remove all loose objects, toys, shoes, etc from the areas to be treated.  For best results, the powder should be applied in a very thin layer barely visible to the naked eye.  To apply a fine layer, shake the container and puff a small quantity of the powder into the target area. Then work the powder into the carpet pile with a soft bristled brush so that it gets down where the fleas tend to live. If applying to upholstery use a hand brush remembering to work the boric acid down into gaps.

After 1 - 2 days vacuum all surfaces treated and vacuum carpets regularly after this as the boric acid will continue to kill both the fleas and their larvae. After a month shampoo carpets.

Miscellaneous uses

Borates including boric acid have been used since the time of the Greeks for cleaning, and other activities. Silly Putty was originally made by adding boric acid to silicone oil. Now name-brand Silly Putty also contains significant amounts of elemental silicone (silicon binds to the silicone and allows the material to bounce 20% higher).

It is used in pyrotechnics to prevent the amide-forming reaction between aluminum and nitrates. A small amount of boric acid is added to the composition to neutralize alkaline amides that can react with the aluminium. Boric acid is popularly used among fire jugglers and fire spinners dissolved in methylated spirit to give a bright green flame.


  • Synonyms: Boron; Boron Trioxide Trihydrate; Boracic acid; Hydrogen borate; Orthoboric acid
  • CAS No.: 10043-35-3
  • EC Number: 233-139-2
  • Appearance: White granules
  • Molecular Weight: 61.83
  • Molecular Formula: H3BO3
  • Melting Point: 169 deg. C ( 336.20F)
  • Specific Gravity: 1.44 (water=1)
  • Solubility in water: 4.9g/100g @ 20C
  • pH: 3.6-4 (4% aq. soln)