Moles can do a lot of damage in just a few days. On a lawn this means a heartbreaking mess, but in the vegetable garden it can mean sudden death for whole rows of plants. The internet is full of mole repellant devices and chemicals, but sadly none have been proven to work consistently. Even trapping can be a hit and miss affair, unless you pay to have it done professionally. But there is hope; most of the damage made by moles occurs in the first few weeks of their arrival, usually in late winter or early spring. If you can put up with this initial burst of activity, once their tunnel network is complete they are relatively easy to live with.
The first sign that you have a mole is the appearance of a heap of excavated soil thrown up on the surface of a lawn, vegetable or flower bed – a molehill. Once a mole’s territory overlaps with yours, you can expect to see quite a few more hills appearing as the mole expands its tunnel network, so if you’re going to do anything you need to do it quickly. But what?
Molehills may seem bad enough, particularly if they are appearing on a pretty lawn that you’ve worked hard on. But moles can be bad news in the working garden too, as their activities can disturb the fine roots of young plants, causing sudden death from dehydration. Worse yet, moles often follow the line of a carefully dug bed, almost as if they are planning their activities to maximise the damage. No wonder gardeners are so keen to get rid of them!
The web is full of chemicals and devices aimed at persuading moles to move elsewhere, including ultrasound devices, rattling windmills and bulbs from the onion family. Although they may work in some circumstances, sadly none of them have been shown to work consistently because soil structure is so very variable: a sonic deterrent may work really well at one end of your garden, but not at all at the other. This is why customer reviews for all these products are so very mixed.
Repellents are typically better used as a mole preventative, making one area less attractive for hunting than another.
There are several types of mole trap available in the UK, including some sold as humane. They are tricky to set properly – mostly you will find that Mr Mole has thoughtfully stuffed them full of earth – and so the job is best done professionally. Even so, trapping your resident mole is a temporary solution at best: if you have a mole there are almost certainly more nearby, so it won’t be long before your garden is recolonised. This means that if you choose to trap, it will have to be a regular activity.
Learning to live with moles
Although the damage caused when a mole sets up a new home can be quite impressive, once they have finished laying out their tunnel network (usually by mid spring) things settle down a bit. Provided you don’t accidentally collapse part of the network, activity is limited to occasional housekeeping so there are very few new hills.
Moles are solitary creatures, so there is only one for each tunnel network. Once established, the network will consist of motorways (long, fairly straight tunnels) linking multiple hunting warrens (relatively shallow twisting mazes with multiple dead ends). The mole puts the hunting warrens wherever the soil is good for worms (read, wherever a gardener puts compost) and collects them as they fall into the tunnels. The motorways, on the other hand, are used to move quickly from one area to another. Moles often put these along the edges of walls or paths because this makes them less likely to collapse. Hunting warrens are sometimes abandoned if they are badly damaged, but motorways are energetically maintained.
Making a mole fence
If you’ve decided to live with moles elsewhere on your plot but still want to keep them out of the veg garden, you can build the underground equivalent of a stock fence. This works really well, although it’s not easy (unless you have a mechanical digger to hand). Dig a trench 30cm (1″) wide and as deep as you can make it – at least 60cm (24″), but 90cm (36″) is ideal – around the area you wish to protect. Fill it with coarse gravel and cover it back up.