How do I prevent pests in indoor herbs?
Written by
Michael Sullivan
Reviewed by
Prof. Samuel Fitzgerald, Ph.D.Preventing pests for indoor herbs starts with some preemptive care. Fungus gnats, spider mites, and um, aphids tend to attack when conditions are right for them. I had lost a crock of basil to gnats before I discovered that cinnamon could keep them away. Something simple, non-toxic, and basic can keep your herbs growing healthy without pests.
Cinnamon Soil Treatment
- Sprinkle ground cinnamon thinly over soil surfaces
- Disrupts fungus gnat larvae development
- Reapply after watering to maintain effectiveness
Sticky Trap Placement
- Hang yellow traps 2-4 inches above herb foliage
- Captures adult gnats and whiteflies mid-flight
- Replace every 10-14 days or when fully covered
Plant Quarantine Protocol
- Isolate new herbs in separate room for 14 days
- Inspect daily for webbing, spots, or insects
- Treat infestations before introducing to main garden
Excess water for too long creates a breeding ground for pests. Let the soil dry out 1-2 inches deep between watering. Gnat flies lay their eggs in the moist topsoil. After switching my rosemary to bottom-watering, I could not kill it. Combine this with airflow from a fan (buy a small fan) to slow the spread of mites or other pests and create stronger stems in your herbs.
Companion Planting
- Grow chives nearby to repel aphids
- Basil's scent masks thyme from thrips
- Marigolds deter soil nematodes
Organic Sprays
- Mix 1 tsp neem oil + 1 quart water
- Spray undersides of leaves weekly
- Wipe residue to prevent photosensitivity
Keep an eye on herbs in the evening: many pests like to eat at night. Your flashlight can also help to look for mealybugs on stems or mites hiding under the leaves. Monitoring shrubs and herbs in the evening gives you time not only to see but also to take action right away to remove them before they spread further. Watching for pests will help to ensure a healthy indoor garden throughout the year.
Read the full article: Growing Herbs Indoors: The Ultimate Beginner's Guide
