If you're getting into worm composting, one of your first questions is probably, "What kind of worms do I need?" It seems like it should be simple — just toss some worms in a bin and let them eat, right?
Not quite. The type of worm you choose has a massive impact on how well your composting operation works. Not all worms compost effectively, and using the wrong species is one of the most common beginner mistakes.
At Wired Worm Farm, we raise multiple species of composting worms, and we've seen firsthand how each one behaves in different environments. Here's the full breakdown of the best types of worms for composting — and why the choice matters more than you might think.
Why You Can't Just Use Any Worm
There are over 6,000 species of earthworms on the planet, but only a handful are suitable for composting in a bin environment. The key distinction is between three ecological categories of earthworms:
1. Epigeic worms (surface dwellers) — These worms live in the top layer of organic material. They eat decomposing matter on or near the surface. These are your composting worms.
2. Endogeic worms (topsoil dwellers) — These worms live in the upper soil layer and eat mineral soil mixed with organic matter. They don't do well in bins.
3. Anecic worms (deep burrowers) — These worms create deep vertical burrows and come to the surface to feed. They need deep soil columns and won't thrive in shallow bins.
When you go dig a worm out of your backyard garden, you're almost certainly finding an endogeic or anecic species. Tossing those into a worm bin is a recipe for failure — they'll try to burrow, won't eat the food you offer, and will likely die.
For worm bin composting, you need epigeic worms.
The Best Types of Worms for Composting
1. Red Wigglers (Eisenia fetida)
The #1 composting worm worldwide.
- Size: 2–4 inches
- Color: Reddish-brown with yellowish banding
- Temperature range: 55°F–80°F (optimal: 70°F–77°F)
- Composting speed: Fast
- Reproduction: Very prolific — populations can double every 60–90 days
- Best for: Indoor bins, outdoor bins, small-scale and medium-scale vermicomposting
Red Wigglers are the default choice for a reason. They eat voraciously, reproduce quickly, tolerate crowding, and thrive in the shallow, organic-rich environment of a worm bin. If you're new to composting, start with Red Wigglers.
2. European Nightcrawlers (Eisenia hortensis)
The versatile all-rounder.
- Size: 3–6 inches
- Color: Pinkish-gray to blue-gray
- Temperature range: 50°F–80°F
- Composting speed: Moderate (slower than Red Wigglers)
- Reproduction: Moderate
- Best for: Composting + fishing bait, outdoor bins, cooler climates
European Nightcrawlers are larger than Red Wigglers and do double duty — they're effective composters AND excellent fishing worms. They're slightly more cold-tolerant and work well for gardeners who also fish. They process material a bit slower than Red Wigglers but produce larger castings.
3. Indian Blue Worms (Perionyx excavatus)
The speed demon of composting worms.
- Size: 2–4 inches
- Color: Dark blue-purple to iridescent
- Temperature range: 65°F–85°F (very sensitive to cold)
- Composting speed: Very fast — among the fastest processors
- Reproduction: Prolific
- Best for: Warm-climate composting, tropical regions, fast turnaround
Indian Blue Worms (also called Malaysian Blue Worms) are incredibly fast composters. They process organic waste more quickly than Red Wigglers in warm conditions. However, they're extremely cold-sensitive — temperatures below 50°F can kill them. They're also known for being "escape artists," often leaving the bin during barometric pressure changes or when conditions aren't ideal.
Best for: Experienced composters in warm climates.
4. African Nightcrawlers (Eudrilus eugeniae)
The tropical powerhouse.
- Size: 5–8 inches
- Color: Dark gray to purple
- Temperature range: 60°F–85°F (die below 55°F)
- Composting speed: Fast
- Reproduction: Prolific in warm conditions
- Best for: Tropical and subtropical composting, large-scale operations
African Nightcrawlers are large, fast-eating worms that excel in warm environments. They produce substantial castings and reproduce well when conditions are right. However, they absolutely cannot tolerate cold — a single cold snap can wipe out an entire colony.
Best for: Warm-climate composters, commercial operations in tropical regions.
Which Worms Should YOU Choose?
Choose Red Wigglers if:
- You're a beginner
- You live in a temperate climate
- You want the most forgiving, reliable composting worm
- Your primary goal is producing worm castings
Choose European Nightcrawlers if:
- You want composting AND fishing bait
- You live in a cooler climate
- You want larger worms
- You don't mind slightly slower composting
Choose Indian Blue Worms if:
- You live in a warm climate (year-round 65°F+)
- You want the fastest possible composting
- You're an experienced worm composter comfortable with more sensitive worms
Choose African Nightcrawlers if:
- You're in a tropical or subtropical region
- You want a large composting worm
- You have temperature control capabilities
Can You Mix Species in One Bin?
Yes — with some caveats. Red Wigglers and European Nightcrawlers can coexist in the same bin without major issues. They occupy slightly different niches and generally don't compete aggressively.
However, mixing species with very different temperature requirements (like Red Wigglers with African Nightcrawlers) creates management challenges because optimal conditions for one species may be harmful to the other.
When in doubt, start with one species and learn the ropes before adding a second.
The Worm You Should NOT Use for Composting
Common garden earthworms (Lumbricus terrestris) — the big worms you dig up in your yard — are NOT composting worms. They're deep-burrowing anecic worms that need vertical soil columns and will not survive in a shallow worm bin.
If someone tells you to just "go dig up some worms from the garden" for your worm bin, politely correct them. Composting requires epigeic species.
Get the Right Worms from Wired Worm Farm
At Wired Worm Farm, we raise and sell healthy, active composting worms — including Red Wigglers and European Nightcrawlers — shipped directly to your door.
Browse our selection at wiredwormfarm.org and start composting with the right worms today.