Agar 1% Borax Based Bait

Recipe #2

Agar bait is slightly more complicated to make than the liquid bait but it is more easy to manage and, especially in hot weather, it is a better way of keeping the concentration of Borax at 1%.  Agar is stabler and has a higher melting point than gelatine and gelatine will not work as a substitute.


To make one litre of agar gel you will need:

To prepare:

  • Put 2 1/2 cups of cold tap water in a saucepan
  • Add 1 tbspn Agar powder
  • stir and let it soak for five minutes
  • Turn on the hob to medium heat and add 250g sugar to the saucepan
  • Stir to ensure agar and sugar are mixed and do not stick to the bottom of the saucepan
  • Let it boil
  • To check that the agar has completely melted dip a stainless steel spoon into the mixture.  Take it out. If the agar sticking on the spoon is clear it has melted, if it looks grainy or sandy return it to the heat until it is clear and glassy.
  • Turn off the hob
  • In a litre measuring jug mix 10g of Borax with1/2 a cup of hot boiling water
  • Pour Borax mixture from jug into the saucepan containing the hot agar/sugar solution. Stir it well until the mixture is clear
  • Return the mixture to the 1 litre measuring jug
  • Add boiling water to make up to exactly1 litre
  • We add a drop of food colouring to increase visibility and identify batches
  • Pour the mixture into trays eg take away containers
  • Leave to set at room temperature (keep in fridge clearly labelled)


You will need lots of screw top jars and, ideally, your neighbours.

  • Once set slice gel into 3-4 cm cubes
  • Place a cube in each jar
  • Make a 4 mm hole (too small for a bee) in the lid of each jar and screw on to jars
  • Place jars i.e. ‘baiting stations’ on their sides in shady places (to stop the bait drying out and becoming more concentrated) around the outside of your property and its perimeter.  if you are also using a repellent bait do not place the stations nearby.  The ants like bark chip and nest in moister places.  They use scouts so an ant trail may march right by initially.  They will find the stations but will also be sensitive to climatic variation and avoid areas where there are repellents.
  • Check and refresh the baits every week or two.  If they are feeding it is working.
  • Try to co-ordinate wih neighbours.  This method requires lots of patience.  The bait will accumulate in the queens and eventually destroy them, at this low concentration it will not directly kill the workers. They are the means to get it to the queens.
  • The colonies/nests/queens will reduce in size/ numbers in the cooler months eg below 12 degrees celsius but it is still worth placing baits as the ants will continue to forage and could be travelling from several sections away.
  • Rouse your neighbours and step up the application programme in Spring/ October when the ant colony will start to expand and they will be looking for ‘honeydew’ type food sources.
  • Keep a record of which bait you and your neighbours are using and when, where, how, and whose turn it is to make the next batch.

What is Borax?

Borax is a common household product and a naturally occurring mineral salt, it is of limited toxicity to humans and pets and this method uses it in low quantities.  Research is being done into whether it poses a risk to pregnant women and care should be taken with it.  If you get it in your eyes flush them out with water.  In case of accident The National Poisons Centre provides 24/7 information at 0800 POISON (0800 764766).

Important Information

Correct storage: we recommend all chemicals are stored in a locked cupboard so they are out of reach of children.

Labelling: if someone is storing the made up solution, they need to write the ingredients and concentrations on the bottle in case of poisoning. It is illegal to store chemicals in containers that used to store beverages or food due to the risk of poisoning.

Laying the bait: bait should be laid in areas where children and animals cannot access it. If this is not possible a bait station should be used.

First aid: a link to the National Poisons Centre website where current first aid practices are listed is available here.

Poison advice (NZ): 0800 764766 (0800 POISON)

Poison advice (World): + 64 3 4797248
Admin: + 64 3 4797227
Fax: + 64 3 4770509
Health professionals:
Parents and caregivers: