Wire worms love fleshy roots like potatoes, radishes, parsnips, and carrots. They don’t usually kill a plant but will leave a gardener’s labor of love riddled with holes and nicks that are only discovered after those tasty root crops are pulled from the ground. Some damage by these villains can be mistaken for slug or snail damage but remember, slugs and snails are surface feeders. Holes in produce occurring underground are from voracious wire worms, the larvae of the click beetle. Organic gardeners have an advantage over the conventional gardener since the click beetles are notorious for their rapid recovery rate from chemical pesticides. These thin, yellowish grubs leave behind veggies that can be salvaged by cutting out the damage in the kitchen. The best prevention of wire worm damage starts in the seed bed.
Tips for Setting up the Wire Worm-Free Garden
You have several practical, easy, organic solutions for preventing wire worms from attacking your crops beginning with your initial planting and stretching through the growing season. Options for preventing wire worms include:
- Top Dress with Coffee Grounds or Used Black or Green Tea Leaves
- Protect with Wheat Seedlings
- Deter with Old Cabbage Stalks
- Set Wire Worm Traps
1. Top Dressing to Prevent Wire Worms
Both used coffee grounds and used tea leaves are highly acidic and rich in tannins, which makes an unpleasant environment for click beetle larva. After planting your seeds, sprinkle the soil’s surface with used coffee grounds and tea leaves in a thin top dressing. Each month of the growing season, refresh this top dressing with the compost of your favorite drink. When planting potatoes, put a layer of coffee grounds or tea leaves on the soil bearing your newly planted spuds and then coat this with a hefty layer of mulch. The nitrogen from this treatment is good for the plants as well.
2. Protecting Crops from Wire Worms with Wheatgrass
Planting a thin line of wheat berries in the spring between your root crops offers many benefits to the garden. Wire worms are attracted to wheat and can be dug up and either thrown to your backyard poultry for snacks or destroyed. Wheat provides a viable green manure that can be turned under to refresh the soil if no wire worms are discovered in its roots.
3. Deterring Wire worms with Cabbage
Old cabbage stalks are wonderful wire worm traps. Simply split the stalk and push it 2-3 inches into the ground near your vulnerable root crops. Remove and replace the stalks when they become filled with larvae. The nice thing about this technique is cabbage is a winter crop. When its season is finished, it’s time to plant spring crops that are vulnerable to wire worms.
4. Setting an Organic Wire Worm Trap
Old potatoes or carrots can serve as traps by skewering several of them with sharp sticks or barbecue skewers with a colorful ribbon tied to the top of the stick. Bury the trap a few inches underground with the ribbon-wrapped stick clearly marking the spot. Every few days, dig up the traps and check them. If wire worms are detected, destroy and replace the trap.