Lesson 8
Are nematodes safe? — the gentle nuclear option
Set your region to personalise this lesson.
Biological controls like nematodes are often misunderstood. They sound technical but they're some of the gentlest, most precisely-targeted tools in the organic toolbox.
Nematodes are microscopic soil-dwelling worms. Different species target different pests — and only those pests. They are widely available by post from garden suppliers in spring through autumn.
What's safe, what's targeted
- Slug nematodes (Phasmarhabditis) only affect small soil-dwelling slugs. They do NOT harm earthworms, pets, bees or people.
- Vine weevil nematodes (Steinernema / Heterorhabditis) attack only the larvae that chew plant roots. Adult weevils still need hand-picking. Pollinators are not affected.
- Both products are safe for pollinators — they don't infect bees, butterflies or other garden helpers.
- Best results: apply to MOIST soil in warm conditions (10–20°C). Repeat through the season for full effect.
Nematodes have a short shelf life and need refrigerating — order only when you're ready to use within a fortnight, and water in straight away.