Starter guide
Hatch a box of caterpillars and watch them spin real silk in five weeks.
Silkworm raising means keeping the caterpillars of the domestic silk moth in an open box indoors, feeding them mulberry until they spin cocoons. They are about the easiest insect to keep: 5,000 years of farming has left them unable to fly, bite, sting or climb out of a tray. A hatchling an eighth of an inch long grows to three inches in about a month, then wraps itself in a single thread of silk several hundred yards long. Daily care is ten minutes of feeding and clearing droppings, and one batch gives you every stage from egg to moth to the next generation's eggs.
Egg, silkworm, cocoon, moth
The domestic silk moth goes through four stages: egg, caterpillar (the silkworm), pupa inside a cocoon, and moth. Nearly all the work is in the caterpillar stage. Eggs hatch after one to two weeks of warmth, the worms eat for four to six weeks and shed their skin four times, then each one spins a cocoon. Two to three weeks later a white, furry moth comes out. The moths cannot fly and have no working mouth, so they mate, lay eggs on whatever paper you give them and die within about a week. The whole cycle fits in a shoebox-size bin on a shelf.
Tick these off as the batch grows
What you can raise in your first month
A box of full-grown silkworms
Worms that arrive half an inch long are three inches and as thick as a pencil about three weeks later.
A growth record
One photo a day beside a ruler shows the four molts and the size jumps better than memory does.
First cocoons
Small live worms usually start spinning inside the month, and each cocoon is finished in two or three days.
Chow
Dried, ground mulberry leaf with a gelling agent. Mixed with water and cooked, it sets into a firm green block. It is available year-round and carries no pesticide risk, which is why this guide starts every batch on it.
Fresh leaves
Free if you have a tree, and worms grow fastest on them. Leaves from any mulberry work, and white mulberry is the one silk farms grow. Pick from trees you know are unsprayed and away from busy roads, rinse them, and dry them completely before feeding. A sealed bag of leaves keeps about five days in the refrigerator.
The switch only goes one way
Worms raised on chow take to leaves at any age, but worms that have eaten leaves usually refuse chow afterward. If your tree leafs out for only part of the year, stay on chow.
Nothing else works
Lettuce and leaves from other trees will not raise a silkworm to a cocoon.
The last week is the hungry one
A silkworm eats most of its lifetime food after its fourth molt. Budget your chow or your tree for that week, not for the quiet first three.
Open one to see where to start. Silk Reeling can add its hand reel to the kit.
Start here
Order 25 to 50 small worms rather than hundreds, and tape a card to the bin where you write the date of arrival, each molt and the first cocoon.
Start here
Raise at least 20 worms to cocoons, because a usable thread is several filaments reeled together. Read a reeling walkthrough before they spin: you have about a week after spinning to reel or to let the moths out.
Start here
Buy eggs by the few hundred, keep them in the refrigerator, and take out a pinch every week or two so worms of the right size are always coming along.
Moisture kills faster than anything
A closed lid traps damp from the food, mold grows, and a bacterial infection can take the whole bin in two days. Keep the bin open and never feed wet leaves.
Germs come in on hands
Wash before every feeding. A worm that turns dark, limp or leaks fluid is sick. Take it out with a paper towel right away and change the lining.
Chemicals you cannot see
Flea and tick treatment on a pet you just petted, bug spray, plug-in air fresheners and tobacco residue on fingers can all kill silkworms. So can leaves from a tree near a sprayed lawn.
A cool room stalls everything
Below about 70°F worms eat little and eggs may sit for weeks without hatching.
Too many worms
200 hatchlings fit on a playing card. A month later they need several bins and food twice a day. Start with 25 to 50.
Allergies
Moth scales and dried droppings bother some people's eyes and airways. Wipe the bin out with a damp paper towel instead of shaking it, and stop if you start wheezing.
Never release them
Domestic silk moths cannot survive outdoors. Freeze eggs you do not want before throwing them away.
Moths come out in the morning, pair within hours and may stay joined for most of a day. A female then lays 300 to 500 eggs on the paper under her. Eggs start out yellow, and fertile ones turn gray within a few days. Eggs of most strains will not hatch until they have been through a cold spell: seal the paper in a container, keep it in the refrigerator, and bring it back to room warmth in spring when the mulberry trees leaf out or whenever you have chow ready. Some strains sold for feeders skip the cold spell and hatch in about ten days, so ask the seller which kind you have.
Wormspit
A silk reeler's notes and photos on raising domestic silk moths and working their cocoons, written from years of doing it at home.
Silkworms for Classrooms
A teacher's rearing instructions with a schedule of what to expect each week.
INaturalist
Point the app at a leaf to check that the tree you found is a mulberry.
Reptile keepers nearby
A local reptile club or exotic-pet store often has someone raising silkworms who will sell a few dozen worms or spare eggs.
Free places to read and identify
The worms and their chow are the only parts you buy again. Everything else is washed and reused for years, and keeping your own eggs takes the worms off the list too. The bin is deliberately plain: silkworms stay where the food is, so they need floor space and open air, not a cage. The heat mat and thermometer are there because the usual reason a first batch fails to thrive is a house kept at 68°F. Cocoon holders are cardboard tubes and egg cartons from the recycling. The hand reel belongs only to silk reeling, so it sits behind that add-on.
Compare the options on each line, then set your tiers and check out from the cart. Clicking a card selects it there, and clicking the selected card again takes that line out. The hand reel stays out of the kit until you switch Silk Reeling on.
Small live worms skip the fiddly hatching stage and reach cocoons soonest. Eggs cost less per worm and let you see the hatch.
Check the listing ships live to your state and that someone will be home on delivery day. Worms sold in a cup arrive with a few days of food in it, and an egg kit may pack a starter portion, so you still need chow of your own.
Silkworms eat only mulberry, and this is mulberry in a form you can keep in the cupboard and cook a batch from whenever you need it.
1/2 LB Powdered Silkworm Hornworm Food (Mulberry Leaf Diet Food) Silkworm Chow
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Dry powder keeps for months sealed and cool. Cooked chow goes in the refrigerator in a sealed container.
A smooth, shallow bin holds the worms and their food, lets you see them from the side and washes clean between batches.
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A shoebox-size bin holds about 25 full-grown worms. Use the lid only for carrying: day to day the bin stays open.
Laid over the worms with fresh food on top, a mesh sheet lets them climb up on their own, so you lift the whole colony off its droppings without handling a single worm.
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Cut a sheet to fit inside the bin. Check the hole size in the listing: holes near an eighth of an inch suit worms under an inch long, and bigger worms need a quarter inch or more to climb through.
Growth rate depends on temperature, and a reading at the bin tells you whether a slow batch is cold or sick.
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Stand it beside the food, not on the heat mat.
Silkworms grow at 78 to 85°F, warmer than most houses are kept, and gentle heat from below is the simplest way to get there.
MET Certified Seedling Heat Mat, Seedfactor Waterproof Durable Germination Station Heat Mat, Warm Hydroponic Heating Pad for Indoor Home Gardening Seed Starter(10" x 20")
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BN-LINK 10" x 20.75" Seedling Heat Mat with Thermostat Controller Combo Set
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Slide it under one end of the bin with a folded towel between mat and plastic, so the worms can move off the warm side. Watch the thermometer for the first day.
Worms under half an inch are too fragile for fingers. A soft brush sweeps them onto fresh food without crushing them.
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Keep it for the worms only and rinse it in plain water.
Reeled silk has to be wound onto something as it leaves the pot. A niddy-noddy turns it into a measured skein you can dry and wash.
1, 1.5 & 2 Yard Adjustable Niddy Noddy for Spinning and Winding Yarn
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Any size works. Smooth arms matter more than length, since wet silk snags on rough wood.
