Moles in the garden: good or bad?

Are moles in the garden good or bad? For those of us who enjoy keeping a prim and proper garden, the infamous dirt mounds that moles leave behind are an eyesore. However, this little animal’s burrowing does have its uses.

For many, a mole in the garden means trouble. The unmistakable, round mounds of bare soil are a clear sign of a mole’s presence. Read on to find out whether moles are considered pests or beneficial garden animals.

Why do moles come into gardens?

In spring they reappear – those circular mounds of excavated soil atop our lawns left behind by moles after digging out their underground burrows and storage chambers. There is a reason why molehills appear in gardens primarily in spring. Moles generally breed from February to April, during which time the male moles go out in search of a suitable female. Throughout the breeding season, they dig numerous new tunnels in order to cover long distances. On top of that, young moles often leave their home tunnel and look for new habitats. This is why moles appear in our gardens again and again.

Advantages of having moles in the garden

Though it may be hard to believe at first, having a mole in your garden actually has a number of benefits. By digging through the garden soil, mixing layers and creating tunnels, moles engage in what is known as bioturbation. This helps to aerate the soil and allows it to absorb more oxygen, which benefits the roots of the surrounding plants. It also loosens to soil, allowing plant roots to grow more freely, which is especially desirable for root vegetables. In addition, this loosening of the soil structure allows rainwater to run off better, especially in heavier soils, which helps to prevent waterlogging. Even the molehills themselves are a gift to gardeners, as the loose, crumbly soil is perfect for using as a growing or planting soil.

Many other beneficial insects are subtenants of moles’ tunnel systems. Ground bumble bees, for instance, build their nests in the tunnels, and it is not uncommon for wild bees to use molehills as a breeding ground. In this way, having moles in the garden can increase biodiversity. The fact that moles are also classified as insectivores points towards another advantage of these small earth-dwelling mammals – grubs, snails and snail larvae are part of its daily diet. A male European mole consumes almost 30kg of animal food per year. In this way, the mole also serves us gardeners by indirectly protecting plants from pests.

Disadvantages of having moles in the garden

Of course, there are also a few disadvantages of having moles in the garden, the most obvious being molehills. These unsightly mounds create more work for us gardeners as we must get rid of them before mowing the lawn to avoid putting unnecessary strain on the blades of our lawnmowers. It is also annoying to have to patch the holes in the lawn by overseeding.

Moles also do not distinguish between beneficial insects and pests, so will sometimes feed on the odd earthworm, which are actually good for our soil. And it is not only ground bumblebees that use the mole’s tunnels, but earth wasps and voles too. Once the mole has moved on, voles (Arvicolinae) use the tunnel system and can cause great damage to vegetables, fruit trees and flowers. Hence it is not a great idea to drive moles away, as this tends to draw in unwelcome successors.

Tip: It is important to learn to recognise the difference between voles and moles. Whilst you are legally allowed to control voles in your garden, this is not the case for moles. This affects what you can and cannot do to deal with the two underground dwellers.

Moles in the garden: what to do?

Many people wonder what to do about a mole in the garden. Before you do anything, it is important to know that moles are protected by the Animal Welfare Act, so it is illegal to kill them. Poison baits or fatal traps are therefore strictly prohibited.

The only method that is permitted is scaring them away. Moles are almost blind, but all the more sensitive to smells and sound. You can actively drive the mole away with strong-smelling household products, such as butyric acid or alcohol, by sticking cloths soaked in these substances deep into the tunnels. Alternatively, you can crush garlic cloves and put them in. Sound waves also disturb moles, and regular lawn mowing has proven to be a good mole deterrent. The vibrations and noise disturb the mole and it is very likely that it will move on. As a prophylactic measure, you can install a mole grid or a mole protection net horizontally in the garden soil before laying out your lawn, and then spread a 10cm layer of soil over it as a base layer for the lawn. Vertical mole barriers that you sink into the soil along the areas that need protecting can also help, as moles rarely move aboveground.

Tip: The effectiveness of acoustic signals, such as beepers, as mole deterrents has not been proven. And on that note, crown imperials (Fritillaria imperialis) are not an effective remedy against moles either, but they are beautiful flowers nonetheless.

So, should you drive moles out of your garden? In principle, having a mole in your garden can be a good thing, because this carnivore can help to reduce the number of annoying pests such as grubs. Moles are also useful in terms of biodiversity. And perhaps the fact that they could potentially help with soil aeration and drainage is enough to make you overlook any negative prejudice against them. And if moles are causing you trouble, you will not need to share your garden for long. Moles seldom live for more than three years and usually live alone.