The best mulch types that will not attract ants include bark mulch, straw and sugar cane mulch. Dry mulch or those with a mix of leaves and stems will be the perfect cover for your soil and keep the mulch to less than 3 inches thick. Avoid mulches with visible sap which is a sweet, sticky substance release from trees that ants love.
What kind of mulch does not attract ants?
Mulch that does not attract ants include straw, sugar cane, bark mulch, tree mulch, pebbles or stone and grass clippings. My favorite mulch, tree mulch will break down quickly and improve the soil while still preventing weeds.
Dry mulches will not contain any ingredients that will attract ants except if they have bits of orange, red or brown sap.
Top reasons ants are in mulch
The top reasons you can see ants in your mulch include the fact that they may have already been living in your soil, the mulch contains sap or the mulch is laid too thick.
Ants are already in your soil
Placing mulch on top of soil that already has an ant population can seem like the mulch attracted the ants. Instead, the ants can live in the soil and the mulch simply provides a cover on their homes.
Ants often move out of the space if their holes are covered with mulch. Some ants will persist and keep their homes in the soil. If you are planting in the soil, the extra watering can often cause the ants to naturally move their home away from the area.
Mulch contains sap
Mulch that contains a lot of sweet sap can attract ants. Orange sap that comes from the trunk of trees when they are damaged. The tree releases this substance to cover the cut and is often sweet and can attract ants.
How to keep ants out of mulch
Here are my top ways to keep ants out of mulch including checking the area before laying mulch, check the mulch for sap and do not lay the mulch too thick. Let’s explore each of these methods
Check the area before laying mulch
Before you lay mulch onto soil look for signs of ants nests. Sometimes you can see a few ants walking across the soil but underneath, thousands of them can be living together. A covering of mulch can provide them with extra shelter and they may end up crawling up and over the top of your mulch.
This will make it look like the mulch attracted the ants but in fact the ants were already there. The mulch just encouraged them to crawl up and over the top of the mulch where you can see them.
Deal with the ants before laying mulch
Dealing with the ants before laying mulch may be needed. The best way to discourage ants is to keep food scraps sealed away in compost or worm farms. If you have an in-ground compost pot, place a lid on top and cover it with sugar cane mulch to discourage ants.
Large ants nests including bull-ant nests may need a different solution and I recommend contacting a pest controller to get advice about what to do about this problem.
You can discuss the options with the pest controller which may be necessary to protect your kids and pets from nasty ant bites.
Check the mulch for sap
Mulch that contains lots of sap which can look like a dark red, orange or brown substance can attract ants. Sap can come from a range of trees including maple, eucalyptus or pine trees. If the mulch contains lots of sap you may find that ants can be attracted to the area.
Avoid laying mulch too thick
Laying mulch too thick can provide a protective layer that can attract ants. Mulch layers that are thicker than 3-4 inches can keep the layers of soil underneath dry, which can make the perfect home for ants.
Ants love shelter so can find a nice home under a large pile of mulch.
The easy solution is to keep the mulch to a maximum of 3 inches. This will allow rain to penetrate through to the soil and to any ants that are looking to make their home. This can discourage ants and keep your garden clear.
Keep your citrus healthy
Another reason that ants can be attracted to mulch is if you have diseased plants, particularly citrus. Citrus that have been attacked by aphids will attract ants which can live in your mulch.
Aphids excrete a sticky substance that will encourage ants to climb up the tree. Ants will hide in the mulch and come out to eat the substance released by the aphids.
Treat the aphids on your citrus trees with eco-oil and this will help to discourage the ants.
Does mulch keep ants away?
Mulch will help to create a balance of insects, soil bacteria and can actually help to keep ants away. I have always found that ants will come and live in open soil areas, particularly sandy spaces and when I have added mulch they are no longer digging holes and creating homes in my yard.
Adding mulch to the top of your soil will increase the amount of organic matter in the soil, encouraging worms, soil bacteria and can keep ants away. A moist, organic mix can discourage ants that prefer a dryer area to live.
Adding plants is another great way to discourage ants, particularly because you will be watering the plants which can get into the ant holes and drive them away.
Why are there so many ants in my mulch?
Sometimes when you get a large delivery of mulch you can also get a large delivery of ants. Most ants that come with the mulch will disappear when you place a thin layer on your garden beds.
Mulch that contains a lot of sap can attract ants and at landscape suppliers the ants are free to roam around and come to collect the sap.
When the ants are moved they tend to disappear over time.
Do wood chips attract ants?
Wood chips on their own do not attract ants unless they are covered with sap. Wood chips that are dry, mixed with leaf and stem matter are generally not attractive to ants. Large piles that are kept thick can provide a sheltered home for ants, so follow the general rule of keeping the mulch less than 3 inches.
Does mulch attract ants?
Mulch has not attracted ants when I have used it around my home. Dry, wood chips, hay, straw or sugar cane are great natural mulches that do not have anything in them that will attract ants. Look out for orange sap and avoid using these fresh, sappy mulches at home.
I am an accredited practicing dietitian, experienced gardener and a dedicated cook. I love writing and sharing my experience so you can learn from my successes and mistakes.