What size is a Medium Dubia roach and how do I harvest them out of my colony?


Everyone squanders over the sizing of dubia roaches. While to some a medium is ¾ of an inch, to others a medium is ½ inch. But just how and why are there different “medium sizes"?

When I harvest my medium dubia roaches, I use a gravitational bucket system. After separating adults, The juvenile dubia get sorted into a tiered system. Mediums come out of the middle bucket as you can assume. These then get put through a secondary square screen to filter them a little bit more. Anything that falls through the ⅝ inch hole but doesn't fall through the ¼ inch hole is what I consider mediums. 

How did I determine what hole size to use when harvesting roaches? 

To determine the hole sizes, I worked backwards from what I thought would be a good medium sized roach in length then found measured how wide they were. Since dubia roaches grow roughly 1-1.25” before becoming adults, I considered a 1” dubia as a large roach, a ½” dubia as a medium and a ¼ inch dubia as a small. Simple right? It seems that way until aiming for perfection when harvesting. As the dubia fall through the holes in my buckets they separate in sizes. But they don’t always fall through to perfection. Often a few mediums or even smalls will end up in the large dubia section; some smalls will end up in the mediums etc. Sifting takes time and patience. 

Once my mediums fall through said holes, I take them and put them into an additional sifter. This is always an optional step, but I think it filters out the “small-mediums” in the process. Those that just aren't quite ready to be a medium but are just too big to be considered small. These will take about 2-3 more weeks of growth before they can be sold as a medium. 

Weighing out medium dubia

You don't really count out 1000 dubia when shipping, do you? No, each morning or night when I am packing orders after sifting dubia to their respective size, I count out 100 dubia roaches and weigh them. Typically, 100 medium dubia roaches are equal to 30 grams. Therefore, when I pack orders, I ship 32g of medium dubia roaches for a 100 count. In general, 1000 medium dubia roaches will range from 280-310 grams. This depends on when they were fed last. 

Want to find out what other drill bit sizes I use? Click on my next blog which talks about a full process of harvesting dubia!

Want to learn how to make a dubia sifting system? Let me know in the comments and I will be sure to make a video!

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