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It may seem a bit odd to learn how to raise mealworms at first. Why would you ever want to have a supply of worms?
Mealworms are not like the redworms you have in your worm composter. They won’t produce valuable worm castings for use in your garden. But they do have other benefits, and they’re certainly easy enough to cultivate.
Today, we’ll look at every aspect of how to grow mealworms, from the life cycle of the worms themselves to how to provide a good habitat for them. Whether you’re interesting in raising mealworms for profit or raising mealworms for chickens, you’ll find all the information you need here!
Why Raise Meal Worms?
A favorite snack of chickens, mealworms provide a protein source for all sorts of critters. People who keep chickens, turkeys, geese, or ducks will easily benefit from growing their own supply of these tasty treats.
But mealworms aren’t just for avians. If you have pet reptiles or rodents, you might just find they’d love to snack on mealworms too. Rats and hamsters in particular are quite partial to them, and most mice will enjoy them too. Pet hedgehogs and ferrets also find mealworms appealing.
Some fish are also very fond of this protein source, and in fact, live mealworms can be raised as bait for fishing. Trout consider mealworms a favorite. Bluegills, catfish, sunfish and crappies are also reported to be lured by mealworms as bait.
Even dogs and cats might enjoy a few mealworms from time to time, as they’re mostly fat and protein. It won’t hurt them, and it’s a healthy supplement to their diet. If your four-legged omnivorous pets seem tempted by your mealworms, feel free to share.
Mealworms are also raised as food for humans, although many of us might get a bit disgusted by the prospect!
Dry-roasted mealworms are said to taste similar to peanuts, and in fact can be used in recipes in lieu of nuts. Those of us who are a bit more squeamish can grind up the mealworms and add them into baked goods for a protein boost that we can’t see.
Whether you plan on supplementing your egg layer’s diet with added protein, or selling your supply to the local bait shop, raising mealworms is easy to do.
And, if you find your supply is overwhelming, mealworms can be dehydrated or dry-roasted for later feed use. Dried worms will float, so they aren’t good for fishing, but they make an excellent treat at the local koi pool or duck pond.
Life Cycle Of Mealworms
The mealworm life cycle is in four stages: egg, larvae, pupa, and darkling beetle.
Female adult darkling beetles can lay hundreds of eggs during their lifespan. These eggs are about the size of a speck of dust and are sticky. Shaped like tiny white beans, they will rapidly disappear into whatever bedding material you opt to use.
When the egg hatches, a larva emerges. These larvae are the mealworms you’ll want to feed to your pets or use as bait. Initially, the mealworms will be very small, but over their roughly 8-10 week larval stage they will rapidly grow to reach 1.5″ in length.
These brown larvae have a hard exoskeleton which protects the fragile bodies inside from their environment. As they grow, they will outgrow their exoskeleton and moult. A mealworm will moult up to 20 times during its larval phase.
On the final moult, what emerges is not a light brown mealworm, but a whitish pupa.
Pupae do not eat or excrete waste. While they have buds where legs and wings should be, they are nonfunctional. These pupal forms can wriggle, but are extremely fragile and should be left alone to mature. This phase will take 1-3 weeks.
Finally, when pupation ends, an adult darkling beetle will emerge from the pupal form, shedding its skin one final time. Initially, the beetle is white, but as its exoskeleton hardens it darkens in color from brown to black. Darkling beetles do have hard wings, but are incapable of flight.
Adult darkling beetles take a couple weeks after emerging from pupal form to mature, but then begin to mate. Females will crawl into their substrate or bedding and lay their eggs there, beginning this cycle again. Darkling beetles will live up to three months in this adult stage before dying.
What Do Mealworms Eat?
When considering how to raise mealworms, it’s important to know what they’ll eat. And in reality, there’s a surprisingly wide variety of options which can be used.
The first food and the most used food is the substrate, or bedding, that you will be raising your worms in. They will eat it, live in it, and poop in it, so it’s very multi-purpose.
Deciding what to feed mealworms can be as simple as buying a container of quick-cooking oats. These dry, flattened oats make a good substrate, but you’ll need a couple inches of them covering the bottom of your habitat container.
Other bedding foods include cornmeal, wheat bran, ground up cat or dog food, breakfast cereals such as Wheaties or Cheerios, and even wheat flour. If you’ve got a box of cereal that’s past its prime, or some old dog kibble, use it – just avoid sugared cereals or things that might attract other insects like ants.
Your second food choice is going to provide the moisture that mealworms need to survive. While their substrate should remain relatively dry so it does not mold or smell bad, the meal worms still need some moisture to thrive in their habitat.
Most people select foods like chunks of potatoes or carrots, as these take a while to mold. However, you can opt to use watermelon rind, apple slices, lettuce or spinach leaves, or other fruits that will maintain their shape for a while. Avoid citrus fruits and softer fruits like bananas or plums, as those break down too quickly.
If your secondary food begins to develop mold or wilts to a point where it is starting to break down, remove it and compost it or throw it away immediately. These foods will need to be regularly changed out as they begin to decompose.
Substrate or bedding food can be used for three to four months before it needs to be changed out for fresh bedding. Worm wastes will build up in it over that period of time, and they make great fertilizer, so don’t just throw it away! Save it and add it to your compost pile, or work it directly into the soil.
Mealworm Container Design
Now, let’s talk about your mealworm habitat. There’s a number of different options out there, but they all have a few things in common:
- Use deep containers with smooth sides
- Ensure there’s good ventilation, either by using a mesh lid or providing some form of airflow
- Keep your mealworm container in a warm location (70 degrees Fahrenheit is optimal).
How Deep Should My Mealworm Bin Be?
Mealworms cannot climb more than a couple inches above the top of their substrate. Ensure you have a container that has room for bedding, a couple inches to prevent climbing, and a little extra space for worms that might pile up on top of the substrate.
I personally prefer a container that’s at least a foot deep, but you can use anything up to the size of a large Rubbermaid storage bin – it just depends on how many worms you want to raise! Remember, the larger the container, the more substrate you will need, and the more worms you will be able to grow.
What Type Of Container Do I Need?
The easiest option for many first-timers is to keep mealworms in an aquarium tank. You can buy a ten-gallon rectangular aquarium for a relatively low price. Mesh aquarium lids are available as well, which provides the airflow necessary to keep the worms happy.
If you’re a DIYer, you can opt for a cheaper container by buying a large plastic bin and doing some modifications to it. You will need to add a mesh panel (I prefer window screen material) for most of the lid to allow for the necessary airflow. You might even want to add extra ventilation along the top portion of the bin, again putting mesh in place.
Some crafty people have disguised their mealworm bins by building them out of old three-drawer plastic storage cabinets.
To do this, you will need to cut most of the bottom out of two of the drawers, leaving enough of an edge so you can glue some mesh screen in place to act as a floor. You will also need to add ventilation panels in both the outside of the cabinet and the drawer sides, again with mesh screen panels keeping the worms inside.
The mealworm eggs and beetle and worm poop will fall through the mesh into lower drawers over time, and you will have to rotate your mealworm colony a bit more often as they work through their life stages. Putting darkling beetles in the top drawer, pupae and older larvae in the middle, and the young larvae in the bottom is usually easiest for care purposes.
Where Should I Keep My Mealworms?
Mealworms grow best at around 70 degrees Fahrenheit. Too much colder, and their growth will slow down. Too much hotter and they begin to die off.
Because of this, it’s best to keep your mealworms indoors in a comfortable room. Since they won’t escape, you can tuck them into a closet if you’d like to hide them. You can disguise them if you build something like the cabinet described above. And, if you have kids, you can place an aquarium of them on a shelf as a living science project.
While mealworms aren’t afraid of light, most of them prefer darker places for their habitat like closets or dark corners. If using an aquarium, you can opt to put paper over the sides to block out some light. Opaque plastic containers will also work well unless you want to be able to peek in at your worms without lifting the lid.
If you plan on raising your mealworms in your garage, you can add climate control during the colder winter months by placing a heating pad set to 70-75 degrees under your worm bin. Summertime can make garages too hot for mealworm farming, so be careful to move them if the temperature rises.
How To Raise Mealworms
Once you’ve gotten your container prepared and decided how to feed your worms, the actual process of caring for them is simple.
Starting Your Mealworm Farm
Ensure there’s at least 2-3 inches of substrate in your container. Place pieces of potato or carrot at random into the substrate. Then, simply add your worms.
Right about now, you may be asking “So, where can I buy mealworms?” That really depends on how many you want to start out with, and how large your container is. I like to order mealworms online and have their habitat prepared in advance so I can put them in as soon as they’re delivered.
Be certain when buying mealworms that you actually get mealworms. Anything that’s sold as extra-large mealworms may actually be waxworms, a different species, and those will not reproduce. Some people sell “super worms” which are also extra-large and which may be sterile.
I prefer to order from a source such as this one where you have the option of getting mealworms in various parts of the larval stage.
When ordering, it’s important to pick at least two different ages of worms so that they can develop a continuous breeding cycle. So, for instance, order small and large mealworms when starting out. You can always add another batch later if necessary. Over time there will be worms in all stages of development, but initially it takes some time to build the colony.
Maintaining Your Mealworm Farm
Your worms have arrived! Now it’s time to get them settled into their new home. From here, the process of how to raise mealworms becomes surprisingly easy.
Place your worms into their bedding, make sure they have their moisture source, and… walk away.
No, really, just walk away. If you want to be nice, you can sprinkle a little extra bedding over top of them to tuck them in, but they can find their way downward on their own.
Check on them frequently to make sure that the moisture source is not beginning to spoil. I recommend checking your mealworms once per day. I personally prefer chunks of carrot as my moisture source, and usually I only need one or two for a 10-gallon aquarium habitat. If the carrot begins to dry out, I replace it.
Be watchful for grain mites. These tiny little whitish pests can develop in environments that don’t have enough airflow. If you develop a grain mite issue, you will need to carefully separate the mealworms from their substrate and replace it. You can compost the remaining substrate with no problems.
Every 3 months or so, replace the substrate. If the substrate ever begins to feel damp, replace it so it doesn’t grow mold. If an aroma develops, replace the substrate. Dry mealworms are happy mealworms!
Changing The Bedding
Eventually, it will seem as though you have more dust in the bin than bedding. That dust is known as frass, and is actually a mixture of darkling beetle and mealworm poop and tiny fragments of leftover substrate.
This video will show you an easy way to separate out your beetles and worms from the frass. Be sure to keep the frass in a ventilated container for a little while with a piece of carrot to allow any eggs or worms that got through to grow large enough to strain out, then simply add them to your refreshed colony!
Frequently Asked Questions
Q: Can I use high-protein chicken feed meal for my mealworms?
A: Yes! Chicken meal will work extremely well as a food substrate for your mealworms.
However, check the label very closely. Any meal that contains food-grade diatomaceous earth should be avoided. The super-fine particulate of diatomaceous earth may be harmless to us and our animals, but it’s like millions of tiny razor blades to a mealworm. Your worms will get cut, dehydrate, and die off.
High-protein meals don’t tend to produce any better mealworms than a container of quick oats do. If you want to save some money, you can just opt for a cheap container of quick oats. But high-protein meals do help your worms to fatten up quicker, which means you can generate more worms in the same amount of time.
Q: My beetles seem to be attacking my mealworms!
A: You probably don’t have enough moisture in there for them. If the environment is completely dry, your beetles will start attacking the larvae for their required moisture. Either add another piece of carrot, or add a lightly-dampened cotton ball that’s been tucked into an old bottlecap to keep it off the substrate.
Check regularly to be sure that your moisture source is fresh. I recommend a daily peek in your colony to be sure everything is going well.
Q: Can I refrigerate live mealworms for later feed use?
A: Absolutely! Be careful, though. Putting mealworms in the fridge means that you are causing them to go dormant. While they can survive in a refrigerated container for up to a couple months, and should not transition into beetles during that time, they also aren’t eating much.
It’s essential that you provide them something to consume if you store your worms this way. A bit of bedding and one piece of carrot or potato in a small, ventilated container should provide them what they need to survive.
It’s also important that you check on your worms regularly to make sure all is well. Too much moisture can cause mold growth, and you don’t want that.
A good storage container for your refrigerated worms is one of these deli food storage containers with holes poked in the lid for airflow. Try to avoid stacking them, as this will reduce the airflow and cause moisture to build up inside the containers.
Ready to make the plunge into mealworm farming? You’ve learned how to raise mealworms now, and it’s really simple to do. You can always sell off your excess to the local pet stores or bait shops! Is there anything which I haven’t covered that you’re curious about? Ask your questions down below and I’ll try to answer them.
