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Mealworm Farm

Mealworms are one of the easiest, cheapest, and most space efficient ways to raise protein for you or your animals.

If you are looking for a way to raise your own protein cheaply, easily, and with almost no space or infrastructure, look no further than mealworms. When food is scarce, you’ll want livestock that are efficient, take up small spaces, and can easily be hidden.

Protein is one of the most expensive supplements to buy, and yet it is an essential component of any omnivore’s diet, whether they are pig, poultry, canine, human, or other. We give our mealworms to all of our omnivores, including our dogs, and they all love them. The chicks and ducklings are especially crazy about them, and using them as a feed source not only ensures a very healthy growth rate, but also makes them unbelievably tame.

Mealworms are even a great food for people. They are very tasty, with a slightly nutty flavor and a pleasant texture. You might decide to raise them for your animals, but if push comes to shove, you may be glad to have them for yourself. This could quite possibly be the food of an uncertain future.

Within this article, we will show you how to build a multi-tiered mealworm farm. It costs very little to make ($30), can be completed in a couple of days, uses about 1.5 square feet of space, and will produce about 1-1 ½ pound of mealworms a week. We will also talk about the care and feed requirements of your bugs, and how to integrate them into possible Food Webs.

Buy a Starter Batch of Mealworms

Materials & Tools

mealworm-materials

mealworm-tools

Materials

8 x 8 ft. long 1”x2” lumber

1 ½” Wood screws (x 150)

17 x storage baskets

Aluminum foil (18” wide heavy duty is preferable)

Window screen

Nylon

Silicon

Paint

2 x plastic containers (for donuts) – roughly 4” tall that open into two 2” parts

Wheat bran and oats

Tools

Scissors

Silicon gun

Tape measure

Marker

Wood saw (circular saw is best)

Drill

Drill bits

Square

 

Step 1: Dimensions

The dimensions of the Mealworm Farm are dependent on the storage baskets you use. We found some at the Dollar Store that are perfect, and cost a dollar each. Use whatever you can find locally, preferably about the same height as ours, and then adjust the dimensions accordingly. To help you do that, here is how we decided on our dimensions:

  • Our baskets are 3 ¼” tall. You want at least ¼” between each basket, so the distance from the top of one rail to the top of the one below is 3 ½”. There are 17 baskets, which makes a total height of 59 ½” (and we added an extra ½” to round it up to 5 ft. tall).
  • The dimensions of the top lip are 18 ¼” long and 14” wide, and the walls then taper. This lip will sit on top of the rails with the basket part sliding in between.
  • The dimensions of the top of the walls, right under the lip are 16 5/8” long and 12 ¼” wide. We therefore made the rails 12 ½” long and the distance in between the inside of the two rails 16 ¾”.
  • The 2”x1” boards are a little less than an inch thick, more like 7/8”. So the support pieces of lumber need to be the 16 ¾” mentioned above plus 1 ¾” on either side (7/8” for the upright board and 7/8” for the rail), making a total of 20 ¼”.
  • The foil and screen to line the baskets must also be adjusted to fit your baskets. The bottom of our baskets are 15” x 11”.
  • At each stage of your tower construction, you should check your work with the trays, making sure they slide easily but cannot fall off between the rails.

 

Step 2: Structure

Remember to account for the thickness of your wood saw when measuring and marking your boards. We use a circular saw, which adds 1/8”. If you’re using a handsaw, you will want to reduce this to 1/16”.

  1. Out of 4 of your 8 ft. boards, cut a length of 60”, 20 ¼” and 12 ½”. This will give you 4 upright pieces (60”), 4 support pieces (20 ¼”) and 4 of the 32 rails (12 ½”).
  2. Cut the remaining 4 boards into 12 ½” pieces. You should get 7 per board. We marked ours at 12 ½”, 25 1/8”, 37 ¾”, 50 3/8”, 63”, 75 5/8” and 88 ¼” from the left-hand side, and then cut to the right of each mark (this allowed for the 1/8” width of the saw blade).
  3. Pre-drill two holes in last 2” of both ends of each rail. The holes should be just wide enough for the wood screws to pass through. These baskets will not be very heavy, so you can probably just put one screw in at each end if you wish.
  4. Pick the straightest edge of each of your upright boards and label that end with a “B” for bottom. Put a “T” on the other end for top.
  5. From the “T” end of each board, make a mark every 3 ½” (3 ½, 7, 10 ½, 14, etc.). It’s a good idea to take something that’s 3 ½” tall and check that you marked each one correctly, as it’s easy to make a mistake.
  6. Lay two of your upright boards down on a flat, level surface. Butt the “B” ends up against something straight like a chest of drawers, and move them 12 ½” apart at the top and bottom.
  7. When you have them both level with each other, the correct distance apart, screw a rail flush with the very top and one near the bottom, right below one of your marks. Please note that you will not be putting a rail in the very bottom space – this basket will sit on the floor instead of on a shelf.
  8. Then screw in the rest of the rails, below the lines you marked.
  9. Repeat for the other two uprights. You will now have two ladders with a whole bunch of rungs.
  10. Lay the two ladders front side down on a flat, level surface, with the rails facing in towards each other. Make sure that they are 20 ¼” part, from outside to outside.
  11. Take your 4 support boards and pre-drill two holes in both ends. One hole wants to be in the middle of the outside inch and the second hole wants to be in the middle of the next inch.
  12. Place a support flush with the top to bridge the two ladders. Screw it in place with only one screw at each end.
  13. Do the same at the bottom of the unit.
  14. Stand your tower upright and check that it is square. If it isn’t square, you will need to twist and shift it slightly until it is.
  15. Screw a support flush with the top on the front.
  16. If everything is square, put the final support somewhere in the middle on the back of the unit, and then put the second screw in each board.
  17. You can now paint the structure.

 

Step 3: Basket Overview

Mealworms are the larvae of the darkling beetle. There are four main stages in development: adult beetles, eggs, larvae (worms), and pupae. The four should be kept apart to avoid the adult beetles eating any of the helpless pupae or eggs, and to be able to better cater to each stage.

This tower is designed to contain three separate modules, each containing a tray for adult beetles, eggs, nursery, and two trays for growing mealworms (totaling 5 trays per module). There will also be one tray for worms that are ready to harvest, and one for frass (mealworm poop). See the photo for the order in which each tray should be placed. You can change the order to meet your needs, but this is the order we use.

To fulfill the needs of each type of basket, we will be building three different kinds of trays. All of them will have aluminum foil on the sides, as neither beetles nor worms can climb slippery surfaces.

  • The trays for eggs, nursery, and frass, will also have aluminum foil on the bottom, as you don’t want any of the material or babies falling through to the basket below.
  • The trays for adults and worms ready to harvest will have window screen on the bottom, so that frass, powdery feed and/or eggs can fall through to the tray below.
  • The trays for growing worms will have nylon netting bottoms, so that frass can fall through to the tray below, but feed cannot. The worms natural movement with sift the frass for you.
  • We will also make a special habitat for pupae that will be placed inside the adult baskets.

 

Step 4: Foil bottomed baskets
  1. Get out 7 baskets.
  2. Cut a piece of foil 18” x 21 ½”.
  3. Make a mark at 3 ½” across and down from each corner. This 3 ½” perimeter will become the walls of a foil box.
  4. Bend the foil in between two opposite 3 ½” marks towards the center.
  5. Do the same for each side.
  6. Fold (but do not glue) the excess material in the corner against the inside of the box until each corner is a neat right angle, kind of like wrapping the ends of a present.
  7. Put a bead of silicon around the edge of the bottom of the basket as well as on the inside of the top of the walls (not on top of the lip). Put a couple of dabs of silicon in the center of the bottom of the basket.
  8. Place the foil box inside the basket, so that it is well centered. Push it down into the silicon, first in the center bottom, then the bottom edges.
  9. Push the walls of the box out, so that they fit the slope of the basket walls instead of being right angles, and press them into the silicon. Adjust the excess foil at the corners and glue them in place.
  10. Cut off any excess that sticks up over the lip of the basket.
  11. Repeat 2 through 10 for the remaining 6 baskets.
  12. Leave four baskets empty. One will be for collecting the frass that falls through the other trays, and will be placed at the bottom of the tower. Label this one “Frass”. The other three are for the nursery trays, which will be filled by the contents of the egg trays when they are old enough. Label thes three “Nursery 1”, “Nursery 2” and “Nursery 3”
  13. Once the silicon has dried, fill the three remaining trays (for the eggs) with a ½” to 1” layer of wheat bran. Label these “Eggs 1”, “Eggs 2”, and “Eggs 3”.

 

Step 5: Screen bottomed baskets
  1. Get out 4 baskets.
  2. Cut a piece of window screen, 15” x 11”.
  3. Cut two lengths of foil, 3 ½” x 16 ½”, and another two lengths that are 3 ½” x 12”.
  4. Bend the bottom 3/8” of each length of aluminum foil at right angles (this lip will glue to the bottom of the basket, while the upright 2 5/8” will glue to the walls).
  5. Run a bead of silicon around the edge of the basket’s bottom, and also put a couple of dabs in the center of the bottom.
  6. Press the window screen down into the silicon in the bottom of the basket. Do its center first and then the sides, so that it is flat and without wrinkles.
  7. Put a bead of silicon around the top of the walls (just down from the lip).
  8. Hold one of the long sides of the foil stretched out in between your hands. Lower it into the basket, centering it on the side of the basket. Press it into the silicon, doing the top center first and moving towards the edges, and then press its bottom 3/8” lip down into the silicon that has come up through the window screen.
  9. Put a little silicon on the foil going up the corner edges.
  10. Lower the shorter aluminum foil pieces into place, pressing them into the silicon from the center towards the corners. Overlap their edges around the corner, pressing them into the silicon on the other foil pieces. If any silicon has squeezed out at the join, make sure to clean it off well, as worms can climb up silicon.
  11. Repeat 2 through 10 for the other 3 baskets.
  12. Leave one basket empty for your “Harvest” tray. This will be filled with the worms and material from the growing baskets, as they get big enough. It has a screen bottom, so that the feed can fall through to the tray below it, leaving only worms behind, ready to harvest. It should be labeled “Harvest”.
  13. Once the silicon has dried, fill the other three baskets with a ½”-1” layer of oats. These are for the adults. The screen allows the eggs to fall through to the tray below, but doesn’t let the oats pass. Label them “Beetles 1”, “Beetles 2”, and “Beetles 3”.

 

Step 6: Nylon bottomed baskets
  1. Get out 6 baskets.
  2. Cut a piece of nylon netting, 15 ½” x 11 ½”.
  3. Cut two lengths of foil, 3 ½” x 16 ½”, and another two lengths that are 3 ½” x 12”.
  4. Bend the bottom 3/8” of each length of aluminum foil at right angles (this lip will glue to the bottom of the basket, while the upright 2 5/8” will glue to the walls).
  5. Run a bead of silicon around the edge of the basket’s bottom, and also put a couple of dabs in the center of the bottom.
  6. Press the nylon down into the silicon in the bottom of the basket. Do its center first and then the sides, so that it is flat and without wrinkles.
  7. Put a bead of silicon around the top of the walls (just down from the lip).
  8. Hold one of the long sides of the foil stretched out in between your hands. Lower it into the basket, centering it on the side of the basket. Press it into the silicon, doing the top center first and moving towards the edges, and then press its bottom 3/8” lip down into the silicon that has come up through the nylon.
  9. Put a little silicon on the foil going up the corner edges.
  10. Lower the shorter aluminum foil pieces into place, pressing them into the silicon from the center towards the corners. Overlap their edges around the corner, pressing them into the silicon on the other foil pieces. If any silicon has squeezed out at the join, make sure to clean it off well, as worms can climb up silicon.
  11. Repeat 2 through 10 for the other 5 baskets.
  12. Once the silicon has dried, fill all six baskets with a 1”-2” layer of wheat bran. These will be home to your growing mealworms. Label two of them “Growing 1”, two “Growing 2”, and two “Growing 3”.

 

Step 7: Pupae habitat

You will have to let some of the worms pupate, so that you are continually replenishing your beetle stock, whose lifespan is two to three months. It is at this stage that they are most vulnerable, and can be cannibalized by either worms or beetles. For this reason, you need somewhere safe to house them.

The system that we came up with is to put them on a raised, plastic platform inside the beetle baskets. The plastic will prevent the beetles from climbing up to get them, and then, when the pupae hatch into beetles, they can walk off the edge to join the rest of the beetles.

  1. Get out two plastic containers like the ones used for donuts (see photo). They should be about 4” tall, opening in the middle to produce two 2” halves. Ideally, you want the central part to be beveled, so that when they are placed with the walls down like a table, the central part dips down to provide a small lip around the edge.
  2. Cut the two containers in half, producing four 2” tall containers. You can discard one of these, as you only need three of them.
  3. Cut out the walls, about an inch from the corners. The intact corners will keep the platform raised, but the beetles will still be able to move around underneath without getting trapped.
  4. Place one container into each beetle tray.
  5. Put a thin layer (1/4”) of wheat bran onto the top and add pupae as you find them. The wheat bran will give the emerging beetles something to eat until they gain the strength to walk off the edge to the rest of the beetles.

 

Step 8: Farm Management

So your tower is now ready to produce mealworms. Before we get started on the exact details of managing your farm, you should know a little about the life cycle of this insect.

The Darkling Beetle will go through several stages in its life cycle. Things like temperature and moisture can affect each stage, but to get an idea of the time scale, here is a breakdown:

  • A Darkling beetle reaches maturity just a few days after it has emerged from its cocoon. During the 2 to 3-month life span, a female can lay hundreds, if not thousands, of eggs.
  • The egg takes between 4 and 19 days to hatch (average of 12 days).
  • It hatches as a tiny, whitish larva, which is hard to see at first.
  • The larva will go through several molts (up to 20), shedding its exoskeleton as it grows. The last molt occurs about 3 months after it has hatched from an egg, whereby it will be golden brown and between 1” and 1.4” long.
  • If you don’t harvest the mealworm at this stage, it will then pupate, encasing itself in a cream, hard case that doesn’t move much or eat.
  • After 6-18 days, a beetle will emerge. It will be pale brown and weak at first, but will darken to a black, shiny beetle after a couple of days, and the cycle can begin again.

Ideally, you want about 150-200 beetles per module, of which there are three in the Mealworm Farm. This will provide you with about 1-1 ½ lb of mealworms each week. If you start out with less, you’ll want to let all your worms pupate until you reach your desired population. We originally bought about 20 mealworms, and grew our farm from there, but it took a while.

Here is a schedule for one module. You will then want to stagger the second and third module by a week each to ensure constant production.

  1. Place your beetles in “Beetles 1”, with “Eggs 1” on the shelf below them.
  2. After three weeks, empty the contents of “Eggs 1” into “Nursery 1”. You then want to put another ½”-1” layer of wheat bran (or other feed) into “Eggs 1” and put it back below the beetles.
  3. After a further 3 weeks, empty “Nursery 1” into one of the “Growing 1” trays. You will then want to empty the new contents of “Eggs 1” into “Nursery 1”.
  4. After a further three weeks, you’ll need to empty the contents of “Nursery 1” into the other “Growing 1” tray, and then the new contents of “Eggs 1” into “Nursery 1”.
  5. After a further three weeks, you’ll need to empty the first “Growing 1” into the “Harvest” tray, then refill it from “Nursery 1”, and refill “Nursery 1” from “Eggs 1”.
  6. Let the worms sit in the “Harvest” tray for a week, by which time most of their feed will have fallen through the window screen bottom, leaving you with pure worms for use.

To maintain your beetle population, you should wait until a few worms have pupated in the harvest tray. You can improve your breeding stock by selecting the largest and healthiest pupae, as well as the ones that pupate fastest.

 

Step 9: Care and Feed

Mealworms like a warm and dry environment, so it’s best to set up your Mealworm Farm inside your home, where the temperature stays constant. This unit takes up less than two square feet, so space shouldn’t be an issue. They also prefer it a little dark (hence why we don’t have much space in between the baskets), so you can hide them away in the corner of a back room.

These insects are highly efficient at converting feed into protein, with an FCR of 2:1. The most common food for mealworms is wheat bran, a very cheap byproduct of wheat production. You can also give them rolled oats, dried grass, or almost any other carbon matter. They also love dry herbivore manure, like the pellet-type manure that rabbits, guinea pigs or goats produce. You can mix this in with something like wheat bran at a 1:1 ratio.

Mealworms don’t drink water as such. Instead, they get their moisture from vegetable scraps. Each day we give them peels and rinds from all kinds of fruits and vegetables, including carrots, potatoes, sweet potatoes, cucumbers, squash, apples, and so on. You don’t want your habitat to get moist, so avoid wet fruits that rot quickly, like strawberries.

 

Step 10: Integration

Our main preoccupation with food production is the concept of integration. We go into this in a lot more detail in our book “Food Web: Concept”, the first of a series of books on sustainable, integrated food systems, but for the purpose of this article we’ll just give you a brief outline and an example web.

The basic principal is that you can make your resources go a lot further by feeding the waste streams of one node (whether human, animals or plant) to another node that would naturally consume that waste. You can include almost any animal and plant into your web; ours is currently made up of rabbits, different kinds of poultry, earthworms, mealworms, gardens, orchards, and wild plants.

By way of an example, let’s say you live in the city and don’t have much space, but still want to produce your own food. An advantage of living in the city is that you have access to all kinds of waste products, like old bread and wilted vegetables from a grocery store. With these basic inputs, you could raise quail, guinea pigs and mealworms.

You can have a breeding pair of guinea pigs, feeding them fruit and vegetable scraps, and a little grain (from the bread). This pair will produce about 12 babies a year, which you can harvest for meat. They will produce manure (which you can feed to the mealworms, along with some vegetable peels and old bread) and viscera (which you can feed to the quail, along with the mealworms). With such a high protein intake, the quail will give you eggs every day. You can then compost any leftover viscera, eggshells and quail manure, which can fertilize a few flowerpots, giving you some year-round vegetables. Any vegetable wastes from your micro-garden can then be recycled through the guinea pigs and mealworms. So, with very little space and using mostly waste products, you can provide yourself with some meat, eggs, and vegetables. You can also eat any mealworms that the quail don’t want, as the Mealworm Farm described in this article would be enough for a LOT of quail, too many for a city apartment. We eat our worms on occasion, frying them in a little butter and garlic, and they are very tasty. They have a slightly nutty flavor and a pleasant texture, and the kids especially love them.

While the Mealworm Farm will produce protein for humans, it can also greatly improve the efficiency of your other livestock with thoughtful integration.

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