Silkworm Care Guide: Feeding, Housing & Storage

How to Keep Silkworms Alive: The Complete Care Guide

Silkworms (Bombyx mori) are the premium feeder insect of the reptile world — ultra-low fat, soft-bodied, high moisture, and packed with beneficial nutrients. But they're also more delicate than discoid roaches or mealworms. While roaches can survive months on scraps in a bin, silkworms need a bit more attention to stay healthy and nutritious until feeding day.

The good news? Silkworm care isn't complicated. With the right food, temperature, and a clean container, you can keep silkworms alive and thriving for 1-2 weeks at home with minimal effort. This guide covers everything you need to know.

What Do Silkworms Eat?

This is the most important section of this guide, because silkworms eat only one thing: mulberry leaves or mulberry-based artificial chow. They are obligate feeders on mulberry (Morus species) — their digestive systems cannot process other foods. Do not attempt to feed them lettuce, carrots, or other produce. It won't work.

Option 1: Fresh Mulberry Leaves

If you have access to a mulberry tree, fresh leaves are the ideal food. Silkworms eat them eagerly and grow quickly on fresh foliage. Wash leaves to remove pesticides or debris, pat dry, and offer fresh leaves 2-3 times daily. Remove wilted or uneaten leaves to prevent mold.

The challenge: mulberry trees are seasonal (leaves available spring through fall in most climates) and not everyone has access to one. This makes fresh leaves impractical for many keepers.

Option 2: Mulberry-Based Artificial Chow (Recommended)

Commercial silkworm chow is a cooked, gel-like food made from dried mulberry leaves and other ingredients. It's the practical choice for most keepers because it's available year-round, shelf-stable (before preparation), and nutritionally complete.

To prepare silkworm chow:

1. Follow the manufacturer's directions — typically mixing the dry powder with boiling water
2. Stir until smooth and pour into a flat container to cool
3. Once cooled, it solidifies into a gel or paste
4. Slice into thin sheets or small pieces and place in the silkworm container
5. Store unused prepared chow in the refrigerator for up to a week

Feed fresh chow every 1-2 days. Silkworms eat constantly and grow quickly — you'll be surprised how much food they go through.

Housing

Silkworms need a clean, ventilated container. Options include:

• Plastic storage containers with ventilated lids — drill holes or cut mesh panels in the lid for airflow
• Shoe boxes with paper towel lining — simple and disposable
• Dedicated silkworm habitat trays — available from reptile supply stores

Line the bottom with paper towels for easy cleanup. Silkworms produce frass (waste) constantly, and it needs to be cleaned out every 1-2 days to prevent moisture buildup, mold, and bacterial growth. Simply lift the silkworms off the old paper towel (they grip their food, so lifting the food lifts the worms), replace the paper towel, and set them back down.

Space

Don't overcrowd silkworms. They need enough space to move, eat, and grow without piling on top of each other. For 50-100 silkworms, a container roughly the size of a shoe box works. For larger orders, use proportionally larger containers or split into multiple bins.

Temperature

Temperature dramatically affects silkworm growth rate and health:

• 75-85°F: Ideal range. Silkworms are active, eat well, and grow at a healthy rate.
• 65-75°F: Slower growth and metabolism. Silkworms survive fine but eat less and grow slowly. This can be useful if you want to slow down growth to extend their usable feeding window.
• Below 60°F: Silkworms become sluggish and may stop eating. Prolonged cold can kill them. Do NOT refrigerate silkworms — unlike mealworms, cold temperatures are harmful.
• Above 90°F: Heat stress. Silkworms are sensitive to high temperatures and can die in sustained heat. Keep them out of direct sunlight and away from heat sources.

Pro tip: If your silkworms are growing too fast (outgrowing the size your reptile needs), move them to a cooler room (65-70°F) to slow their growth. This buys you extra days before they become too large.

Humidity and Ventilation

Silkworms need moderate ventilation but not excessive dryness. Their food (mulberry chow) is moist, and their frass contains moisture, so the container interior stays naturally humid. The key is balance:

• Too humid (poor ventilation): Mold grows on food and frass, killing silkworms. This is the #1 killer of captive silkworms.
• Too dry (excessive ventilation): Food dries out quickly, silkworms dehydrate.

A container with ventilation holes in the lid provides the right balance for most environments. If you notice condensation forming on container walls, increase ventilation. If food is drying out within hours, reduce airflow slightly.

Handling

Silkworms are gentle, slow-moving, and completely harmless. They don't bite, don't jump, and don't move fast. You can handle them bare-handed without any risk. Their soft bodies are somewhat fragile — pick them up gently, supporting their body, and avoid squeezing.

When transferring silkworms to a feeding dish or tongs for your reptile, handle them by letting them crawl onto your finger or a piece of food rather than pinching them directly.

Storage: Maximizing Shelf Life

Silkworms have a shorter shelf life than roaches or mealworms. Here's how to maximize it:

• Keep at 65-75°F to slow growth without stopping it
• Feed fresh chow every 1-2 days — hungry silkworms decline rapidly
• Clean frass daily — moisture from waste promotes deadly mold
• Don't refrigerate — cold kills silkworms
• Use within 1-2 weeks of arrival for best results

If you can't use all your silkworms before they reach the cocoon-spinning stage (they stop eating and start producing silk), feed the remaining worms to your reptiles immediately — they're still nutritious at this stage, just not for much longer.

Silkworm Life Cycle

Understanding the silkworm life cycle helps you manage timing:

1. Hatchling (1st instar): Tiny, black, thread-like worms. Eat finely chopped chow.
2. Growing instars (2nd-4th): Worms grow rapidly, molting between each stage. This is the prime feeding window.
3. 5th instar (final): Largest size. Worms eat voraciously, then stop eating and begin searching for a place to spin a cocoon.
4. Cocoon/pupa: Worm spins a silk cocoon and pupates inside. Not useful as feeders at this stage.

The feeding window from hatchling to cocoon-spinning is approximately 3-5 weeks depending on temperature. Warmer temperatures accelerate the cycle; cooler temperatures slow it.

Common Problems and Fixes

Mold

The most common silkworm killer. Appears as white, green, or black fuzzy growth on food or container surfaces. Fix: Improve ventilation, clean frass daily, remove moldy food immediately, and don't overfeed (only offer as much chow as worms will eat in 12-24 hours).

Silkworms Not Eating

Usually a temperature issue — too cold or food isn't fresh. Fix: Warm them to 75-80°F and offer freshly prepared chow. Silkworms won't eat dried-out or stale food.

Silkworms Dying

Check for: mold (ventilation), dehydration (food freshness), temperature extremes, or overcrowding. Silkworms that turn brown or black and become mushy have likely succumbed to a bacterial infection from unsanitary conditions. Fix: Separate healthy worms into a clean container with fresh food immediately.

Silkworms vs Roaches: Different Roles in the Rotation

Silkworms and discoid roaches serve complementary roles in a reptile feeding rotation:

• Discoid roaches: High protein (20%), moderate fat (7%), long shelf life, low maintenance — the daily staple
• Silkworms: Lower protein (9%), ultra-low fat (1%), high moisture (83%), shorter shelf life — the premium supplement

Use discoid roaches as your foundation and rotate silkworms in 2-3 times per week for variety, hydration, and the unique nutritional benefits that only silkworms provide. Together, they create one of the most complete feeding programs available for captive reptiles.

— Matt, Founder, All Angles Creatures