How to Protect Potatoes and Carrots from Wireworm Damage

You dig up your first early potatoes or pull a perfect-looking carrot, only to discover it’s riddled with narrow, rusty-brown tunnels. That, friends, is the handiwork of the wireworm. These slender, coppery larvae of click beetles might be small, but they can wreak havoc underground. But fear not, here’s how you can protect potatoes and carrots from wireworm damage without resorting to harsh chemicals.

Get to Know the Enemy

Wireworms are the larvae of click beetles and can live in the soil for several years. They’re particularly fond of root veg like carrots and potatoes, especially in ground that’s recently been converted from grass or pasture.

We find they’re most problematic in the first few years after turning over a new patch of turf, so forewarned is forearmed.

Use Trap Crops to Lure and Destroy

One of our favourite tactics is the humble trap crop. A few weeks before planting your carrots or potatoes, we bury chunks of carrot, potato, or beetroot about 5cm deep in areas of concern. We mark the spots with sticks, then dig them up after a week or so, often crawling with wireworms. Straight into the bin or to the chickens they go.

Repeat a few times to reduce numbers before planting.

Avoid Freshly Sodded Ground

Wireworms thrive in soil that was recently grassy. If you’re planting in a new plot, wait a year before putting in root crops. Instead, grow above-ground veg like beans, brassicas, or salad leaves while the soil settles.

If you must plant carrots or potatoes right away, consider using large containers filled with fresh, clean compost to sidestep the problem entirely.

Rotate, Rotate, Rotate

Crop rotation isn’t just for the books, it works. Try not to grow root veg in the same place two years running (if possible). Wireworms tend to linger in soil, so by switching things up, you disrupt their lifecycle and reduce damage over time.

We keep a simple rotation plan and pair root veg with legumes or leafy crops to keep the soil (and pests) guessing.

Time Your Planting Carefully

Wireworm activity tends to spike in cooler, wetter soil. We wait until the soil has properly warmed before planting carrots and potatoes, usually late April to May. This delays sowing just long enough to avoid their most active window and helps seeds germinate faster too.

Warm soil = happy roots, fewer wireworms.

Keep Soil Light and Well-Drained

Heavy, damp soil gives wireworms a cosy place to hide. We improve drainage and texture by digging in plenty of organic matter or sharp sand, especially in carrot beds. Well-aerated, free-draining soil is less inviting to wireworms and encourages strong root growth.

Raised beds can also help if you’re dealing with persistently wet ground.

Encourage Natural Predators

Ground beetles, birds, and chickens love a good wireworm snack. Welcome them into your patch by planting wildflower strips, leaving a few undisturbed corners, and keeping soil chemical-free. The more diversity in your garden, the more pest-eaters show up to help.

If you’ve got chickens, a bit of pre-season scratching and foraging does wonders for clearing larvae from the topsoil.

Wireworms may be underground pests, but with a little knowledge and a few strategic moves, we can keep them in check and protect our prized root crops. Whether you’re growing for crisp, sweet carrots or buttery new potatoes, a wireworm-free harvest is absolutely possible and well worth the extra effort.