Raising mealworms is a fun hobby and a great way to produce a nutritious and sustainable food source for livestock, reptiles, fish, and birds. They are also gaining popularity as a food source for humans due to their high protein content and potential environmental benefits. The nutrient-rich waste the mealworms leave behind is also a valuable resource for gardeners, farmers, and plant enthusiasts.

What are the stages of a mealworm’s life cycle?

To begin the process of raising mealworms, it is important to first understand their lifecycle because some stages (the beetle and larvae stage) will eat the other stages (eggs and pupa). The 4 stages of mealworms: egg, larva, pupa, and beetle.

How long does it take for a mealworm to complete its lifecycle

The duration of the mealworm lifecycle can vary depending on environmental conditions, like temperature, humidity, and food, and takes anywhere from a few months to a year. Here is an approximate breakdown of how long it takes for a mealworm egg to become a mealworm, pupa then beetle:

Mealworm eggs will incubate for about 4-19 days before they hatch
Mealworms are in the longest stage of the life cycle and will begin to pupate after 2 months or more
Pupa will generally stay dormant for 1-3 weeks before emerging as a beetle
Mealworm Beetles will immediately start laying eggs and live for 2-4 months.

Mealworm Eggs

Mealworm eggs are very small, white/cream-covered oval-shaped, and are usually laid in clusters of 20-30 by the female beetles. They can be used as a food source for small insects and birds if you can find them, and they will also be eaten by mealworms and beetles, so for best results, it’s best to sift out the eggs and let them hatch separately. Mealworm eggs can take anywhere from 1-3 weeks to hatch, depending on temperature.

Mealworms

Mealworms are in the larval stage of the mealworm lifecycle. All stages of the mealworm lifecycle can be used as feed for other animals, but the larval stage is the most important and the most nutritious stage of the lifecycle. To accommodate their growth, mealworms will molt (shed its skin) between 10 and 20 times during their 4-6 week lifespan, and then it morphs into a pupa.

Pupa

This stage is the craziest stage of the mealworm life cycle. During this stage, the mealworm sheds its skin for the last time, forms a hard exoskeleton, and begins a complete transformation internally and externally. Depending on the temperature and humidity of the environment, these pupa will stay motionless and do not eat for around 7-14 days, until it emerges as a soft and light-colored beetle with all its adult body parts, such as wings, legs, antennae, and reproductive organs.

Pupa are vulnerable to being eaten by mealworms and beetles, and for the most productive breeding setup, it is best to separate the pupa at this time. We have come up with a great way to do this, and it is explained in the “mealworm breeding setup” section below.

Mealworm Beetle (Tenebrio monitor)

At the end of the pupa stage, the adult beetle emerges from the pupa case. The newly emerged beetle can be distinguished as a male or female and is initially soft and light-colored, but it quickly hardens and darkens as it dries. The adult beetles have two pairs of wings, but the forewings are modified into hardened protective covers, and they can’t fly.

The beetle will then begin to mate and lay eggs, starting the life cycle all over again. The female beetle can lay anywhere from 100 to 500 eggs in their 3 months lifespan. So once you get it going, it really gets going!

What do mealworms eat?

Mealworms are detritivores, which means they feed on decaying organic matter. In captivity, you can feed them a wide variety of food, but it’s best to use foods that won’t rot quickly or get the substrate soggy. I mainly feed my mealworms potatoes, sweet potatoes, carrots, and dried fruits.

Mealworms are adapted to survive in dry conditions, so their water requirements are relatively low compared to other animals. They obtain moisture from their food, so it’s good to provide them with food that contains a high water content. For this, I will feed them cucumber slices and apples, but I always place them on a paper towel to keep it from causing the substrate to get nasty.

Mealworm Breeding Setup

There are many ways to set up a mealworm farm, but the basics are all the same. No matter how you choose to house your mealworms, if you keep your bins clean and your mealworms fed, they will grow and multiply very fast. Set up your bin properly, maintain it weekly and you will be rewarded with a never-ending supply of protein-packed mealworms and their nutrient-rich waste.

Place your mealworms in a well-ventilated container with substrate (I use oatmeal), in a dark place between 77-86 degrees F. Provide them with a balanced diet of grains, vegetables, and fruit scraps, and make sure to remove any uneaten food regularly to prevent mold. Every few days, sift out the nutrient-rich waste produced by mealworms, known as frass. This is an excellent organic fertilizer. I use it in my compost bins, gardens, and potted plants.

• Build a mealworm enclosure with proper airflow/ventilation
• place it out of direct sunlight in a warm and dry location
• consistently stays between 75-85°F (24-29°C)
• Removing mites and mold quickly using a mite control, if necessary.
• Use an easy-to-clean substrate
• Come up with a regular maintenance schedule to keep the breeding area clean.
• As your population grows, you may want to add additional containers to avoid overcrowding.

There are several different mealworm setups you can use when raising mealworms. We have used a low-maintenance, one-bin setup as well as a more hands-on multiple-bin method. Both setups work just fine, just experiment to find what works best for your situation.

The simple mealworm setup

This setup is meant for people who want to raise mealworms on a small scale with the least amount of work. This one-bin setup houses all stages of the mealworm’s life cycle in the same bin.

You will need:

• 1 Dark Large Bin
• Cardboard. The beetles like to lay their eggs directly on cardboard. Place lots of paper towel rolls and cardboard egg crates in your setup, and every few days, shake the eggs off into another bin to prevent them from being eaten
• Substrate. Most growers use wheat bran, oat bran, or oatmeal.
• Food. Mealworms get their water from eating moist foods, which is just about any fruit or vegetable. This is where most people mess up their setups.
• A Sifter: After a while, most of your substrate turns to dusty, small particles. This amazing fertilizer all needs to be sifted out of the bin.
• Mealworms: You can buy mealworms at the pet stores, but I’ve heard that sometimes they’re treated so they don’t pupate, so I have always bought mine in bulk from Bassett’s on Amazon and they come in a pillowcase-like sack.

Optional:

• A Hygrometer: Use the bin’s lid to keep the humidity in, but use a sharp object (or soldering iron) to poke air holes in it. Use your hygrometer to measure the humidity and aim for 60%. If is too high (over 65%), poke more air holes.

How to: Mealworm setup

Place all your mealworms in the bin. Over the next few days, you will notice they are shedding their skin, and morphing into pupa.

Pupas are dormant during this stage of their life. They don’t eat and they only move (wiggle) when they are touched. They are very vulnerable and can be eaten by other mealworms and beetles if they are hungry enough.

The large-scale mealworm setup

To improve productivity, house each stage of the mealworm’s life cycle in separate bins. It requires a little more work and takes up more space but results in substantially more mealworms than a one-bin system

You will need:

• 2 Dark Large Bins
• Cardboard. The beetles like to lay their eggs directly on cardboard. Place lots of paper towel rolls and cardboard egg crates in your setup, and every few days, shake the eggs off into another bin to prevent them from being eaten
• Substrate. Most growers use wheat bran, oat bran, or oatmeal.
• Food. Mealworms get their water from eating moist foods, which is just about any fruit or vegetable. This is where most people mess up their setups.
• A Sifter: After a while, most of your substrate turns to dusty, small particles. This amazing fertilizer all needs to be sifted out of the bin.
• Mealworms
• Block of wood or Bowl

Optional:

• A Hygrometer: Use the bin’s lid to keep the humidity in, but use a sharp object (or soldering iron) to poke air holes in it. Use your hygrometer to measure the humidity and aim for 60%. If is too high (over 65%), poke more air holes.

Place the pupa on top of a 3″ high block of wood (or upside-down container) in the bin. For now, they are high enough so beetles and mealworms can’t eat them. Once they morph into beetles, they will walk off the block and fall into the beetle pit below.

Make sure your platform is high enough that the beetles and mealworms can’t climb up it.

After 1-2 weeks, the pupa emerges as a white/light brown beetle and will walk off the platform to land below with the rest of the beetles and mealworms. Over the next few hours, it will darken and turn black.

Beetles lay a lot of eggs. If you are patient and maintain your setup, you will end up with a lot of mealworms.

This can be done with any size bins and as many bins as you’d like. Set up and maintain your bins just as I shared above.

The only difference here is you want to continually sort out the life cycles into separate bins.

Separate the pupa into a new bin, or place it on a platform in the beetle bin (as stated in step 3)
Every 2 weeks-1 month, sift out the beetle bin into a new, clean container. You can sift several months worth of eggs into one bin. You will end up with a bin of different size mealworms, or you can keep adding new bins.

Handling and safety considerations

It’s important to consider the proper handling and safety precautions to ensure the well-being of both the mealworms and yourself. Here are some guidelines to follow:

1. Hygiene: Washing your hands before and after handling mealworms to prevent the spread of any potential bacteria or pathogens.
2. Storage and containment: Store your mealworms in a clean and well-ventilated container that is away from direct sunlight and extreme temperatures.
3. Escape prevention: Ensure that your container is secure so mealworms can’t get out, and predators (frogs, lizards, squirrels) can’t get in.
4. Proper feeding: Provide a balanced diet of fresh fruits, vegetables, and grains that are void of pesticides or chemicals.
5. Cleaning: Regularly clean the mealworm container by removing any dead mealworms, feces, and uneaten food and sift out the grass to prevent the buildup of waste and reduce the risk of contamination or odors.
6. Handling equipment: Use a mask when sifting out the frass, as you don’t want to breath it in. Spoons are a great way to remove dead mealworms and pupa.
7. Allergies: Some people may have allergies to mealworms or their byproducts.

Where to buy mealworms

When starting your mealworm farm, be careful buying mealworms from the pet store as sometimes they treat them with a chemical that prevents them from pupating – as they want them to stay as mealworms for feed. I buy mine from Bassett’s on Amazon (HERE), and if you do it right, you’ll only have to buy them once.

How to Maintain your mealworm setup

The key to raising mealworms successfully is keeping a dry, clean, and ventilated environment. Dirty overly moist systems can quickly become infested with mites and mold which can smell and cause harm to the worms.

• Ensure that the container you are using has enough ventilation to prevent moisture buildup.
• Remove any uneaten food or waste before it rots.
• Use an easy-to-clean substrate like oatmeal or bran, and replace it often.

mealworm temperature and humidity:

Too much humidity/moisture is the number one reason mealworm setups fail as too much moisture will encourage mites, and mold and destroy your farm. Keep your humidity level at 60% humidity and proper ventilation (holes in the bin for airflow) will reduce humidity levels.

optimal mealworm temperature:

Mealworms breed faster in warm temperatures, so keep your setup around 80 degrees. Colder temperatures will cause your mealworms to go dormant, preventing them from morphing to pupa (which is why they keep them in the refrigerator at the pet store).

mealworm bedding and substrate:

There are many types of substrate you can use, more on that below, but whatever you chose, make sure you freeze it for a week or more prior to using it in your mealworm setup to kill the mites and eggs that are already in it.

separating life cycles:

You don’t have to separate the different life cycles, but they are cannibals, meaning the beetles and mealworms will eat the defenseless pupa and eggs, so by separating them you will have a better success rate.

feeding your mealworms:

Don’t use really wet foods or your substrate will get nasty. Setting the food directly on a paper towel will help prevent the substrate from soaking up moisture. Don’t let the food rot or go moldy or it will stink and attract bugs.

mites:

Too much humidity (over 65%) will encourage mites and mold. Even the cleanest of bins can develop a mite problem, and you have to catch them early or they will take over your mealworm bin and possibly your house.

If you see mites, you can use reptile spray that will kill the mites on contact. I like to spray it on the walls of the container rather than on the substrate itself, but because of their exoskeleton, the mite spray won’t hurt your mealworms. If you have a lot of mites, it’s best to start over. Pick out all the mealworms, pupa, and beetles and trash the substrate.

cleaning your mealworm bins:

I clean my mealworm bins almost every day if I can. It only takes a few a second and it is a very important step. The more you do it, the less your bins will smell and you can prevent mite issues.

Pour your substrate and mealworms through a sifter, using your second bin to catch the small particles of partially eaten food, mealworm poop/waste (frass), shed exoskeleton, and any unhatched eggs.

This mixture will have to sit in the bin long enough for the eggs to hatch (1-3 weeks). Once the mealworms have grown larger than the holes on your sifter (1-2 months), you can sift out the remaining frass.

Leave the egg bins to sit long enough until all the eggs hatch and the mealworms grow large enough that they won’t fall through your strainer. At this point, it is safe to say the bin only contains frass and no eggs. You can use this frass on your plants. It is a great soil amendment and is actually really expensive as you can see here.

Grow your own mealworm food

We grow all our mealworms’ food in our food forest: Squash, carrots, sugar cane, potatoes, and sweet potatoes. These are all good choices as they last a long time before they go bad. They’ll also eat leafy greens like lettuce, spinach, and kale. There are tons of edible flowers and even many wild plants and weeds in your yard. Do some research on your native, edible plants and feed your mealworms a variety of food.

Frequently Asked Questions about Mealworms

How to make mealworms grow bigger

You can decrease the amount of cannibalism by always having food (carrots, potatoes) available for them to eat.

Why are my mealworms turning brown? black?

It’s probably dead. If it is black and crunchy, it is definitely dead. There are probably many reasons why your mealworms could be dying, but it happens. I feel comfortable feeding the dead to my fish and turtles. I have been doing it for years.

What temperature should mealworms be kept at?

Can chickens eat mealworms?

Raising mealworms for chickens is a great way to provide your chickens with a little extra protein. Chickens can eat a handful of Mealworms in 2 seconds, so if you have a lot of chickens, you better raise A LOT of mealworms!

Do mealworms need light?

How long for mealworm eggs to hatch

How long for mealworms to pupate

Can mealworm beetles climb or fly?

Why are the mealworms hiding under their food?

Why is their skin falling off? Do mealworms shed?

Mealworms shed their exoskeleton to grow. Then after the shedding of their final skin, they morph into a pupa.

Where can I buy mealworms?

I buy mine from Bassett’s on Amazon (HERE), and if you do it right, you’ll only have to buy them once.

What do Mealworms eat?

How do I get my mealworms to grow faster?

What about super worms?

Be careful when purchasing mealworms from pet stores. Some growers treat their mealworms with a chemical that prevents them from pupating. If left to grow, these treated mealworms will just keep growing bigger and bigger. These are named Superworms.

Some pet stores unknowingly sell regular-sized mealworms that have been treated so they won’t pupate in transit. If you happen to purchase these treated mealworms, they won’t cycle through their life cycle and you will be without a mealworm farm.

How long until mealworm eggs hatch?

Mealworm eggs hatch into microscopic mealworms after 1-3 weeks, depending on temperature and humidity. In cold temperatures, the eggs can go dormant until conditions are warmer. After 3 weeks you will begin to see tiny mealworms in the egg bin.

The babies are very hard to see at first. Just stare at the substrate and you will see it moving.

Every few weeks, sift out the small particles from your mealworm colony and you will end up with eggs and frass. Let this substrate sit for a few weeks, eventually, you will be able to start at it and just barely notice that the particles are moving. These are your baby, microscopic mealworms moving around.

Raising mealworms for human consumption – Entomophagy

As resources decline and populations grow, people are realizing eating insects, such as mealworms, is a much more sustainable choice than beef, pork or chicken. Mealworms are a great source of protein that requires less water, land, and food than livestock.

By 2050 the world will hold over 9 billion people, and insects may be key to our survival. It may sound bad now, but just a few decades ago, eating raw seafood wasn’t accepted by American consumers either until the creation of California roll, caused it to quickly gain popularity.

Although in America bugs are usually only consumed as a dare, over 2 billion people in places such as Thailand and China eat insects regularly, even being considered a delicacy. These insects are sauteed, stir-fried, fried or grilled.

Insects such as crickets and mealworms are actually a superfood, containing 80% of protein to body weight.

Raising mealworms for plant fertilizer

Use the small particles of poo and exoskeleton (frass) that you sift out of your Mealworm farm to fertilize your plants. You can use it on your own plants or sell it! It was pretty expensive, considering what it is!

Small particles of mealworm excrement and shed exoskeleton will accumulate over time and will need to be cleaned out. Don’t throw it away! Use it for fertilizer.

*Make sure it sits long enough so the eggs can hatch.

When frass is sprinkled on a plant, it makes the plant think it is being invaded by bugs. This kicks the plant’s autoimmune system into overdrive. It protects itself by strengthening its cell walls and releasing an enzyme (chitinase) which is its own natural insecticide and fungicide. These defense mechanisms make the plant stronger and better able to fight off disease, mold, and pests.

It won’t burn your plants either. The frass can be sprinkled on top, mixed directly into the soil or brewed into a tea. It is becoming quite popular and can be purchased at some plant nurseries or here online.

We are currently experimenting with frass to see how well it works. I will post the results soon.

We get a lot of requests from people wanting to purchase our mealworms. We tried selling them, but unfortunately, we couldn’t keep up with the demand and our chickens, turtles, frogs, and wild lizards were not happy about it. But we have ordered several times from Bassett’s Cricket Ranch on Amazon and they have never let us down.