Garden Pest Control: Protect Your Plants Naturally

Are Nematodes a Biological Control of Garden Pests?

The simple answer to this question is yes: nematodes are among the most effective methods available to home gardeners. Nematodes are microscopic, soil-dwelling roundworms which are parasitic to specific pests, making them highly targeted and safe for wildlife.

There are several types of nematodes, including slug control, vine weevil control, leatherjacket control, and ant control, so gardeners can choose the one that matches the pest they’re dealing with.

For slug control, the key nematode species is Phasmarhabditis hermaphrodita. When mixed with water and applied with a watering can, these nematodes enter slugs’ bodies and release bacteria that cause a fatal infection, stopping them from feeding almost immediately.

Nematodes are a beginner-friendly way to control slugs because they are species-specific, meaning they target slugs without harming earthworms, pets, or wildlife. They are also approved for organic growing systems and work underground, with effects that can last up to 6 weeks after each application.

Apply your nematodes when the soil temperature is above 5°C, water the soil thoroughly before and after application, and apply in the evening to prevent the nematodes from drying out in direct sunlight. Keep them refrigerated and use them within their shelf life, as they are living organisms.

Dealing with Aphids & Flying Pests

Aphids are common pests in the garden, including greenfly and blackfly. They cluster on new growth, sucking sap and excreting a sticky honeydew substance that encourages sooty mould and attracts ants. Left unchecked, a small colony of aphids can explode into thousands within a week. Fortunately, they are one of the easiest pests to manage without chemicals.

A simple way to deal with aphids and other pests is to blast them off plants with a firm jet of water, then repeat every few days if needed. You can also use an insecticidal soap spray made from pure liquid soap and water, or a natural bug spray, and apply it directly to the colonies, as this is safe for most beneficial insects. This method can help a wide range of plants, including roses, beans, tomatoes, peppers, brassicas, and soft young shoots. On broad beans, pinch out any blackfly-covered growing tips, and use fine mesh netting to protect brassicas from cabbage white butterflies and whitefly.

Conclusion & Next Steps

Protecting your garden naturally is easy and just needs a mix of clever planting, physical barriers, and harnessing nature’s own microscopic armies. There’s no single silver bullet; the most successful natural gardeners layer their defences, combining companion planting with physical barriers, biological controls, and a welcoming habitat for predators. The shift away from chemicals isn’t just about following trends; it’s about building a garden that is genuinely more resilient, healthier, and better for the wider environment.

Ready to act? Browse the full range of natural pest controls at Johnsons Seeds and give your garden the natural protection it deserves.