Ants in the trash: why they come and how to wash, bag and place your bin so they stop

Ants in the trash are there because the bin holds what ants look for every single day: food scraps, milk cartons and sweet drink cups that were never rinsed, liquid that leaks through the bag and pools at the bottom, and sticky smears around the rim and under the lid. What works is separating wet waste from dry waste, rinsing sweet containers before they go in, using bags that do not leak and tying them tightly, washing the bin and the floor under it until dry, and moving the bin away from the line ants walk along. If you do all of that and ants still arrive from the same wall every day, there is a nest nearby and you need to trace it.

This article is part of our series on ants in different spots around the home. The bin is often the first place a line of kitchen ants finds food. If ants are in several places at once, such as the bin, the sink and the sugar jar, start by finding the source with the method in ants in the house, then come back and deal with the bin using the steps below.

The main cause is sweet and fatty waste that goes in without being rinsed: milk cartons with milk left in the corners, bubble tea cups, snack bags, sauce sachets, fruit peel and fried chicken bones. These smell strongly from the first day. Foraging worker ants find them quickly and leave a scent trail for the rest of the colony to follow in a line.

The second cause is liquid escaping the bag. A thin bag pierced by fish bones or skewers lets curry and sweet drinks drip into the bottom of the bin, where nobody sees it because it sits under the bag. That puddle smells and gives ants both food and water. A bin that gets a new bag every day but is never lifted out and washed will still have ants circling it.

The third cause is the grime on the rim, under the lid and on the pedal. When you scrape plates into the bin, splashes stick to the inside edge and dry into sticky smears. A bin pushed against a wall or cabinet also becomes a bridge, so ants can walk straight from the wall line onto the bin without crossing open floor.

Ants prefer the wet waste bin in almost every case, because wet waste means food scraps, vegetable and fruit peel and liquid containing sugar and fat. A dry bin with only paper, plastic bags and rinsed bottles has almost nothing for ants to eat. Splitting waste into two bins makes ants easier to control, since only one bin needs close attention.

A dry bin only draws ants when unrinsed containers go into it: soda bottles with a little left in them, condensed milk cans, snack bags with crumbs and takeaway boxes with sauce. Pour the liquid down the sink, rinse or shake the container once with plain water and let it drip before it goes in. That alone takes the dry bin off the ants’ list.

A wet waste bin works better small and emptied often than large and left for days. If you do not make many scraps, put them in a small bag and tie it off every evening. Strong-smelling scraps such as fish bones and prawn shells can be wrapped in a second bag first, which cuts the smell and stops liquid seeping into the bin.

Wash the whole bin, not just the bag. Lift the bag out and tip away any liquid at the bottom. Scrub the base, inside walls, rim and underside of the lid with a long brush and water mixed with dish soap, rinse until the foam is gone, then turn the bin upside down in the sun or wipe it completely dry before the new bag goes in. Dish soap removes both the food residue and the scent trail ants left behind.

The spots people forget are the lid hinge, the pedal, the rod running from the pedal to the lid and the groove under the outer rim. Dirt there is invisible from above but ants reach it first. Use an old toothbrush along the grooves, then wipe the floor under the bin and the wall behind it, because drips from lifting the bag usually land there.

While you have ants, wash the wet bin once a week or whenever you see liquid in it, and wipe the rim every day when you change the bag. If the bin still smells after washing, dry it in the sun for longer or switch to a bin with a smooth surface, since deep scratches in old plastic hold grime better than a new surface.

Choose bags thick enough not to tear and sized to fit the bin. A bag that is too small stretches thin and splits at the rim, and one that is too large folds up at the bottom where liquid collects in the creases. When you change it, press the air out and tie it tightly before lifting it out. Tying first stops spills on the floor and keeps the smell in until it goes out.

Sharp items such as fish bones, skewers and can lids should be wrapped in paper or a small bag first, since they cause most leaks. For leftover soup, strain out the solids and pour the liquid down the sink with the tap running. Never pour soup straight into the bag, because it seeps into the bin even if the bag does not tear.

A tied bag should not wait beside the bin or by the kitchen door overnight. Take it to the outdoor bin or the building’s rubbish room. If you cannot take it out yet, put it inside a bin with a tight lid. A bag sitting on the floor becomes a new spot for ants to find, and the line simply extends from the floor into the house.

Keep the bin far enough from the wall or cabinets that you can see the floor all around it, and not next to the sugar jar, fruit basket or pet bowls. Ants prefer to walk along edges. If the bin stands away from them, ants have to cross open floor where you can see and wipe them easily, and the line does not carry on from the bin to the food beside it.

Outdoor bins should not stand on soil, grass or against a tree trunk, because many ant nests are in the soil around the house. Put them on concrete or a raised base and wash that spot when liquid drips. Bathroom bins, which many people search about, usually draw ants because of humidity and tissues with lotion or sweet drinks on them. Use a lidded bin there and change the bag more often.

If the home has several bins, keep food waste in the kitchen only. Do not throw snack wrappers or sweet drink cups into bedroom or study bins. A bedroom bin with sweet waste is one reason ants walk into bedrooms at night. If you also find ants on the bed, read ants in bed.

Bins ants find harder are ones whose lid closes fully when not in use, with smooth walls and no holes in the base. A pedal or press-lid bin that shuts by itself holds smells in better than a swing lid that often hangs half open, and far better than a bin with no lid. But no bin keeps ants out if the inside is dirty.

Lots of people search for an ant-proof bin, but what stops ants is the upkeep, not the model. An expensive bin holding three days of food scraps gets ants, while a plain bin emptied and wiped every day rarely does. If you replace your bin, look for one that comes apart for washing, has no deep crevices in the lid and is the right size for one to two days of your household’s food waste.

Bins with a removable inner bucket or a rubber seal around the lid help with smell, but the seal has to come off for washing too, or grime under it becomes the ants’ new favourite spot. For bins with automatic lids or other electrical parts, clean them as the manufacturer’s manual says and never wash the motor or battery compartment with water.

A pad works for a small food waste bin whose base is narrow enough to sit in the middle of the pad with at least 5 cm to every edge, as the manufacturer recommends. A 30x42 cm pad therefore suits a bin with a base up to about 20x32 cm, such as a scrap bin on the counter or beside the sink. A large floor bin with a wider base cannot use a pad.

On the product page, one customer review mentions placing the pad under a food waste bin, which is the same use described here. The extra step is wiping the pad whenever liquid or scraps drip on it, because anything on the pad acts as a bridge for ants to cross the edge. See the size and price at anti-ant pad 30x42 cm.

Anti-ant gel can go on a bin stand or shelf legs, which are vertical surfaces, painted as a complete ring on a fully dry surface. The seller has not yet confirmed how well it resists water, so avoid spots that get mopped or dripped on often. Details are at anti-ant gel. Both pad and gel are barriers; neither replaces washing the bin and tying the bag.

Spraying insecticide on a kitchen bin is not recommended, because it is close to where food is prepared, and spray only kills the ants it touches. New ants from the nest replace them the next day. If it is a shared outdoor bin and you really need it, use a properly registered product and follow the label exactly. Never mix products or guess amounts yourself.

If you have washed the bin, changed how you throw things away and moved the bin, and ants still come from the same wall or floor crack every day, the nest is close and the bin is only the destination. Follow the line of ants back to see whether they come through a crack, a pipe gap or the door edge, then wipe the trail and seal the entry where you can.

For ants that keep coming from a nest inside the home, bait that workers carry back to the nest targets the source better than spray, but it must be placed away from children and pets as the label says. How to choose between bait and blocking with a pad is explained in ant bait vs anti-ant pad.