Mealworms

There's alot of information on raising mealworms.  I've tried to adopt what appeared to my eye to be best practices (after going into an OCD research mode). My current production began with 5,000 mealworms.  Sounds like alot, but in reality, it is not once you consider harvesting for your customers (birds etc), allowing to pupate and die off (though that seems to be a very small percentage). I've since ordered 10,000 more.  I've reached the point where my pupa (from first batch) have become beetles.  I don't have a 2nd generation yet.  And even then, it will take weeks for them to reach the stage where I can feed them.  So consider your throughput for feeding and optimize your shipping costs by buying at least 5,000 to start. 

There was one blog in particular that was helpful, but I cannot locate it (it was many pages deep in the google search and my memory cannot recall it) to give attribution but will update this if I find it again (and I've tried!).  She kept meticulous records on what she ordered, harvested, pupated and beetles.  The next best source was Sialis.org   I'm not going that far, but I did want to provide some overview here from a novice point of view of what I consider best practices:

For the care and feeding of your larvae:

1. First and foremost, mealworms (in all of their life cycle iterations) are living beings and should be handled with care and treated well. I've seen folks have all life stages tumbled together (and that works for them) or  stuffed in a container with a tight fitting top (that didn't work for them) and everything in between.  Follow basic common sense and know that all living things require air, moisture and food and protection from element/hazards.  These require less care than your kids.  But optimizing their care will optimize your results.
2. Second:  If you have an aversion to wriggly things, this endeavor is not for you.  The larvae are noisy in their crawling in the substrate, and they wriggle with great gusto when you grab them.  The beetles makes crawling noises in their substrate.  If the feel sounds and sights of this make your hairs bristle, don't do this.
3. Container:  Plastic, smooth sides, ventilated
• Type of container (plastic, smooth sides) and floor space the most important.  (I had an old smoothish sided container.  But due to its age, it was rough enough for a few pioneers to escape.  I had to rehome the batch. Provide adequate room for your worms, with enough wall space that they cannot climb out.  Also, ensure that any that is in your substrate (paper etc) does not come in contact with your cover (ventilated!) because they will climb up and out.  These mealworms are VERY active.  So they are giving off moisture byproducts (just as we do) that also builds humidity in addition to what you are providing. 
4. Mite infestation:  Whatever your substrate, microwave it before introducing to your "farm" to prevent any carryover mite infestation.My forgotten blogsource had this problem, and it was a source of much work to abate. An ounce of prevention as they say. (I've since read that microwaving does not provide a great eradication, and my experience proved me right).
5. Substrates:  Many substrates can be used to provide food and 'cover' for your mealworms.  I buy cornmeal in 50lb bags for my suet production.  I can buy a 50lb bag for less than $20.  I also have wheat bran from the feed store.  Again, 50lbs is about $16.  Whether food grade or feed grade...microwave (or freeze) to prevent mite infestations.  I also put in some finely milled whole wheat flour, ground up cat dry food.  See the Sialis link for excellent nutrition info. (Update:  I've since moved to layer (non-medicated) feed which is cheap and works great.  The wheat bran had a mite infestation that caused me great problems even though I microwaved).
6. Moisture.  The larvae and the beetles require moisture. There must be a balance between too much moisture (causing mold/fungal growth n substrate) v. not enough. The amount of moisture sources you need is commensurate with the amount of mealworms that you have. I have found that my mealworms do much better with providing greater moisture than what I saw recommended. An apple or two or potato or two as week is not cutting it.  So ensure that you are optimizing available moisture.. I found the following to be worthwhile:
1. Potatoes and Apples--If these are sliced very thinly (use your food processor slicing blades, or simply a sharp knife) these can be managed well and provide moisture without any mold detected.Many folks noted that potatoes got moldy.  Mine have not. But they do turn color form oxidation.  If there is enough surface area (e.g. THIN), then the mealworms/beetles can avail themselves to the moisture.
2. Carrots:  Chunkier slices allow the worms to bore through.  I've not notice any mold. (Update:  I find that taking a vegetable peeler and peeling long slices optimizes their enjoyment).
3.  Coffee filters, Handiwipes, unbleached coffee filters dampened with a spray bottle of water are welcomed. They also eat through this.
4. Burlap: This addition seems to be the home run. I have some rough burlap coffee sacks.  I cut pieces of it to use in my mealworm containers.   I use a spray bottle to mist them and fold them in half.  The larvae LOVE to be in between these layers. I HIGHLY recommend.
5. Fresh bread slices.  If it dries out, I mist them. Have not had any mold.
6. Water crystals (for beetles): Personally, I would nix all the other stuff and simply use water crystals. I believe this to be a HUGE best practice. I'm using the water crystals for the beetles, and that is working well.  Soak crystals according to directions. Put them in the fine mesh shipping clothe, and soak in water (like a tea bag).  (I had to cut it and sew a bag with the top open.  Pour crystals in, soak in water and tie off top).  Place on a a protective plastic lid to keep bedding dry.  The beetles can climb on it.  They love it.
• I'm experimenting with these for the larva as well.  I put it in the burlap, and I can already tell that the mealworms are loving it. 
• (Update 07/14/2018)--I had a large amount of my 3rd purchase worms and subsequently pupae die off.  After research, I believe that the humidity level was subpar.)
7. Hiding Places:  These worms like to burrow.  Crumpled up newspaper, brown packaging paper are welcome places for them to hide, and these places make it easier for you to harvest them.  (Pick up paper and shake it out--though be warmed they can flick up and out of your container very easily!).
8. Styrofoam:  The beetles and the worms like styrofoam.  Packing peanuts also loosen up the substrate.
9. Tools.  These are delicate beings.  I recommend the following:
1. Plastic artist canvas (Darice) screen works as a great sifter or to put overtop smaller plastic containers to ventilate (the are rigid enough to make a great top) and can also be used to provide bottoms for self sifting (see below) .  You can fashion a rectangular sifter by cutting the corners diagonally and folding them in (inside one corner, outside the other corner).  You can staple and hot glue.  I found this sifting basket easier to use than a sieve.
• This canvas can also be used as the base in the a self system cannister.
• Worms can still get through this if given enough time!
2. Tweezers.  I have some long tweezers from a medical kit.  These work great for removing dead worms.  You probably don't have to remove them, but I prefer to if I see them.  I would not use these on live pupa--but for dead pupa (which turn greyish black), they are a necessity.
3. Plastic spoon. A plastic spoon allows for gentle removal of pupa (next life stage).  I noted from the blog (that I cannot remember) that too much sifting resulted in damaged pupae causing wing/leg deformities in the beetles.  I've been mindful of that, and keep sifting to a minium. (Update:  I don't sift, yet I still notice some deformities.  So I think that it is simply a matter of genetics).
4. Litter scoop:  I outfitted a litter scoop by lining with the plastic artist canvas and hot gluing.  Very easy to scoop and sift.   
5. Dust mask:  I think that wearing a dust mask is a good precaution.  I can already sense some respiratory irritation.
10. Meal worm hotel.  I am using a 3 drawer Sterilite ($20 from Walmart delivered!) for part of my colony.  I have not added any addition ventilation as there appears to be ample ventilation just in the spaces around the drawers (to include my opening them often etc.).  I will revise if necessary.(Update 07/18, no additional ventilation needed).
• Top Drawer is a self sorting beetle and pupa incubation drawer.  I have a black cryovac container that I cut one end out of.  I placed it upside down so that the beetles can hide under it.  On top, I have pupa in a shallow cardboard stationary box top.  I cut the corners out of one in and pressed flat so there is an escape hatch.
• I cut the bottom out of the top drawer and installed the Darice 12x18" plastic canvas. This method allows self sorting of the eggs, though you have to remember to open both drawers if you are opening the top drawer.
• The second drawer has substrate and is awaiting eggs to drop down and become small larva. I'm not far enough into the process for this.
• I also have other containers with larvae. I think that it is a best practice to to have some separate conatainers for your investment in case there is some sort of infestation.
11. Separating life stages: the mealworm motel is a self contained hotel that keeps life stages separate.  Different folks do different things (like glom them all together.  I don't think that optimizes results, but it might be just fine). Update (I noted pupae in the beetle bin were being cannabilized (with rigor) by beetles). 
• Where I have the larvae substrate, I note that the pupa seem to rise to the top of the substrate. Accordingly, one doesn't need to do alot of sifting to find them.  I also noted in a blog (that I cannot attribute because I cannot find it) that she noticed much deformity in beetles due to sifting for the pupa. I'v heeded her advice and use a plastic spoon   to gently scoop them up and placed in a safe incubation container. I do not recommend tweezers or your hand as either seems to exert too much pressure and causes the to wriggle with discomfort. 
• Once you notice pupa, you essentially have a graduating class.  You will notice more pupa everyday (and throughout the day).
•  Pupa are mummies so they only need ventilation and to stay at proper temp.  I put them in a shallow stationary cardboard box lid mentioned in 10 above.  This way, they are raised up from the beetle fray, safe and comfortable.  When they become a beetles, (and you will be surprised how quickly they begin to turn en masse) they can escape the box lid opening into the beetle substrate. 
• For those needing a little shepherding, I found that cutting a piece of styrofoam egg carton provides a gentle way to maneuver them without harming them. 
• Like the pupa forming from the larvae, once you notice the final metamorphis to beetle, you will notice LOTS of this happening every hour.
12. Other notes/learnings/observations
• Wash hands before and after for your health and theirs.
• You must monitor for escapes.  It happens.  I find beetles out and about (HOW?).  And with any of the paper etc, those worms can easily get flicked off.  There is no harm done, but...
• I noted in a research paper that adding some Brewer's yeast and dried milk powder can boost nutitive value of substrate and provides needed B vitamins.
• They don't smell, but you will be able to smell your substrate.
• This is a fascinating project for kids (though I have adult children and no grandchildren).  And I have to say that I was mesmerized by the pupa turning into beetles.  I'm now waiting on the final stage of the beetles to lay eggs.
• Purchasing mealworms online (I got mine from Rainbow) are 1/2 the cost (even including shipping) of price in store.
• if even you are at home, my worms were in the unairconditioned truck and were quite warm when I got them.  I cooled them down quickly, and there were no ill effects, but I don't think an hour or two more in the mail truck would have done them any good.
• I was surprised how quickly I used up my first 5,000 larva.  My second order was 10,000, and even then I'm wondering "How did I use them so fast!?"
• If you are actively feeding birds or reptiles, realize that you may need much more than you initially think.
• It's not much time.  I'm spending more time just do to my fascination with it, and getting things set up.
• I don't do anything to make things darker in the room. I keep the light off.  There are two windows, and it is pretty dark up there.
• Mealworms are calcium depleting so ensure that you put some calcium (I use pulverized, sterilized egg shells) to coat mine to maintain bone/eggshell producing strength of your customers.
• Besides being an interesting thing to observe, your bird friends (or other grateful cold-blooded recipients which I don't own) will enjoy them.