Ants can both be bad and good for gardens depending on your experience. I believe there is a need for a healthy ant presence in any garden because ants are generally beneficial for plant life. A good sign of an out-of-control ant population is the presence of large numbers of aphids that secrete honeydew.
Read on to learn more about whether ants are good or bad for your garden plants. This post also identifies reasons why you have an ant infestation in your garden and how to manage the problem.
Ants are good for vegetable gardens because they help with pest control and assist with the decomposition of organic material, which is good for plants. Ant species build tunnels that break down the soil, and their foraging activities aid seed dispersal, which is beneficial for garden growth.
The beneficial side of having ants in your vegetable garden
Although I have had a few previous unpleasant experiences with fire (it still hurts!) and carpenter ants in my vegetable garden, I believe that ants are generally good for garden plants. Seeing these critters scurrying about garden beds may not be to everyone’s delight, but the following benefits of having them around may make you have a change of heart.
- Aeration: ant’s tunneling activities help aerate the soil and improve water, oxygen, and soil nutrients to the plant’s roots.
- Soil cultivation: as ants perform their biological activities, they turn over the soil (till) by bringing up buried organic material to the topsoil, which is highly beneficial for garden plants.
- Decompose organic material: ants accelerate the decomposition process of plants and other insects. They feed on organisms that break down into nutrient-rich organic waste, which fertilizes plants.
- Elimination of garden pests: I have observed ants attacking caterpillars which were ruining the lettuce and parsley in my garden. Studies have shown that ants feed on insects that eat healthy plants and spread plant diseases in your garden.
- Pollination and dispersal: by moving seeds around during their food gathering movements. Ants help pollinate flowers and redistribute seeds over your garden bed, aiding the reproductive and germination process.
Aphids – the main culprit of having too many ants
Aphids are tiny, soft-bodied pear-shaped pests that feed on plant sap and secrete a sugar-rich fluid called honeydew, an ant delicacy that is the nucleus of the aphid-ant union. Ants and aphids have developed a symbiotic relationship in which aphids produce honeydew for ants in exchange for protection from predators.
It works this way. During the day, ants guide aphids around plants and guard them while they feed, and carry the aphids to safety within their nests at night for protection.
In return for their trouble, ants feed on the honeydew secreted by aphids, sometimes prodding the aphids with their long antennae to produce honeydew on demand. Ants get to farm aphids to guarantee a continuous supply of honeydew by building enclosures within their nests to prevent aphids from leaving.
Damage to plants
The aphid-ant relationship hurts plants in several ways. While studies reveal aphids feeding is harmless to healthy plants, I have seen aphids cause devastating damage to a wide variety of plants and shrubs in my vegetable garden. Some of these harmful effects include:
- Large aphid infestations can wilt plant leaves or turn them yellow.
- Excessive sap feeding by aphids can stunt young shoots.
- Certain aphid species inflict gall formation on plants and inject growth-inhibiting toxins that also cause leaf deformation.
- Some of the aphid-related crop damage I mentioned earlier is a result of aphid virus transmission between plants. The affected crops in my vegetable garden include beans, lettuce, potato, pumpkin, and chard. I’ve seen broad bean pods turn black due to aphid infestations.
- Certain aphid species, such as lettuce root aphids and carrot crown and root aphids, are disease-causing pests that target specific areas of particular plants, killing the plant.
Signs that your ant population is out of control
I often play a simple game while gardening. It is called ant spotting, and it involves watching out for ants in spots where I haven’t seen them previously. This little game has saved my garden from an ant infestation on numerous occasions. It’s a game that I recommend you play on your own.
The general signs that can help you determine if your garden ant population is out of control include:
- A booming aphid population: if you notice an increasing number of aphids on your plants, then there is a high likelihood that your garden is experiencing an ant infestation. Ants attack and kill aphids’ natural predators (earwigs, larvae, and beetles); to protect the aphid population and maintain the aphid-ant symbiotic relationship.
- Ant nests: ant nests are a familiar presence around any garden, but they become a source of concern when large numbers start sprouting around my vegetable beds instead of the garden edges where there is less chance of disruption.
- Plants with weak roots: significant ant populations can harm your vegetable root systems due to their tunneling movements. This is characterized by stooping, bent, and wobbly plants.
What to look for when checking raised beds:
Raised garden beds with a dry soil system are ant magnets if not watered often. In my experience, checking if the soil system is dry (moist soils repel ants) is a sign that ants are likely to be present in significant numbers.
7 natural ant-control methods
Over time, I have stumbled across several highly effective, natural, and environmentally friendly ant-control methods. These techniques have, on numerous occasions, helped reduce the ant population in my garden without harming the vegetable plants.
Here they are:
Getting rid of aphids
I have often used the aphid-ant symbiotic relationship as an ant-control technique to great success because a decline in my garden’s aphid numbers means fewer ant populations.
I have removed aphids by spraying them off plants with a garden hose and used neem oil or essential oils spray solutions on my vegetables to rid them of aphids. Natural predators like lacewings, ladybugs, and birds can be very useful in eliminating aphids.
I have had a high success rate using zeolite as an ant-control method. This little known ant and slug remedy works great when sprinkled over ants’ nests.
The zeolite’s honeycomb structure and its other unique characteristics can also be exploited for long-term, slow-release pesticide applications, making them highly effective against ants in your garden.
This naturally occurring product has a devastating effect on ants. It comprises millions of microscopic glass-like shards that cut through the bodies of ants, dismembering them or causing other debilitating physical damage.
Diatomaceous earth penetrates ant skin and drains their body of protective fats and other nutrients until they are dead.
This is a personal favorite of mine, and it is so effective at killing ants that it is unreal. Pour boiling water into any ant-hole in your garden to kill the ants inside. The result is instantaneous death for the ants residing in the colony.
White vinegar is an effective ant-control method. I have eliminated hordes of ants from my garden by spraying a 50-50 solution of 5% vinegar and water on infested plants. You can find a powerful vinegar concentrate here.
Borax (sodium tetraborate) is a lethal ant killer that I often use around my garden in spray or powder form. While borax is naturally occuring, you will need to dilute this effective ant-control product with water to make sure you don’t harm your plants with a high dose.
I like to mix borax with sugar and water and place it the vicinity of nests, to attract as many ants as possible.
Oil of Lemon Eucalyptus (OLE)
Eucalyptus tree leaf extract is a safe bio-pesticide with immense ant-control capabilities. The main ingredient is an active chemical compound called p-menthane- 3,8-diol (PMD), making OLE an effective ant repellent.
Learn more about organic pest control methods for your garden in this detailed article.
Like most gardeners, I have a love/hate relationship with ants. I love them for their beneficial effects on plants and hate them because they can constitute a general and sometimes painful nuisance. Either way, I don’t think I would love to see the end of the critters because they make such a vital part of any garden ecosystem.