Do worm castings attract pests?
Written by
Olivia Mitchell
Reviewed by
Prof. Samuel Fitzgerald, Ph.D.Fresh worm castings naturally deter pests with their one-of-a-kind properties. The enzyme chitinase breaks down insect exoskeletons, deterring aphids, mites, and other pests that invade gardens. The adequately processed castings smell like fresh earth rather than rotten foodstuffs, which helps prevent unwanted guests. Having used them for many years, with no pests attached, when used properly.
Freshness Indicators
- Earthy forest-floor scent confirms proper processing
- Absence of ammonia or sour odors means no pest attraction
- Crumbly texture indicates full decomposition
Storage Best Practices
- Use breathable burlap sacks not airtight plastic containers
- Maintain 40-70°F temperatures to prevent microbial death
- Keep in shaded areas away from direct sunlight
Application Safeguards
- Never mix with undecomposed food scraps
- Apply to soil surface then cover lightly with mulch
- Water immediately to activate pest-repelling enzymes
Different pests react variably to the castings. Fungus gnats occur only when castings are wet for weeks. Ants don't like places that have been treated with fresh casts because of the activity of micro-organisms. Slugs go around the treated areas. After I began using the castings regularly in my garden, I found that I had 70% fewer insect pests.
Contaminants often cause the problems with pests. Mixing castings with decaying food creates ammonia, which attracts flies. Wet storage creates mold, which attracts gnats. Always buy from reliable sources. I check every batch by taking a handful and squeezing it to check for moisture and odor.
Extend repelling effectiveness through proper use. Apply when the soil temperature exceeds 55°F so the enzyme can be activated. Use castings in conjunction with companion plantings, such as marigolds, for enhanced protection. I use this combination in my tomato beds, resulting in almost zero pest damage. Reapply after heavy rains to refresh the barrier.
Read the full article: Unlocking the Benefits of Worm Castings
