The Grubhouse is a complete black soldier fly larvae (BSFL) rearing and self-harvesting system. I build each one by hand in Aurora, Colorado, it costs $350, and it's meant for people who want to grow healthy grubs to feed their chickens, reptiles, birds, or fish, or who want to turn food scraps into frass a lot faster than a compost pile does. It's a steel wire-shelf frame with two stacked tubs, walls made of 90% shade cloth instead of plastic, a track around the colony tub that catches larvae when they leave on their own, and magnetic egg surfaces you can pull off in about fifteen seconds.
That's the short version. People keep asking me what it actually is, so this post is the long one.
Why I call it a system and not a bin
A bin is a container. You put larvae in it and hope. I started that way, with an old 27 gallon tub, then a better tub, then a tub with holes drilled in it and a ramp taped to the side. Every one of them went the same direction, moisture built up, the substrate went anaerobic, and the colony either died or left. I don't think that was me doing it wrong. A plastic tub can't breathe.
What I learned over the years raising BSFL is that the people who do this well aren't using bigger tubs. They're managing airflow, managing moisture, giving the larvae a clean way out when they're ready to pupate, and handling eggs on purpose instead of by accident. Commercial BSFL farms run on those principles. The Grubhouse is my attempt to take the same principles and shrink them down to something that fits next to a chicken run.
What's in it
The frame. Steel wire shelving, 24 inches by 18 inches, taller than it is wide so it takes up one tub's worth of ground. Two tubs sit in it, one above the other.
Tier one, the colony tub. This is where the larvae live and where your scraps go. The lid over it has a hatch for feeding and fins across the top that let the bin's smell out. The egg-laying surfaces hang under the lid on magnets.
The Grub Track. When larvae are done eating and ready to pupate, they climb out on their own. Two ramps run out of the colony tub for them, but when a batch goes all at once a lot of them skip the ramps and go straight up the walls. The Grub Track runs the whole way around the outside of the colony tub and catches both kinds, then routes them to a single hole where they drop into the tub underneath. I verified that on the prototype before I'd put it in writing, the wall crawlers do end up in the track.
Tier two, the collection tub. The prepupae land here. This is what you scoop out and hand to the chickens, or let pupate to start the next generation.
The walls. Shade cloth, stretched over the frame, with a door flap at the front so you can get in and manage things. This is the part that matters most, so it gets its own section.
The walls breathe, and that's most of the point
Every tub I built died wet. Shade cloth walls give moisture a path out and keep air moving across the substrate the whole time, which is especially effective in dry Colorado air. The substrate stays aerobic instead of turning into the swamp that every sealed tub eventually turns into.
There's a second reason this matters, and I don't think enough people talk about it. These grubs are food. When a sealed tub goes anaerobic, stagnant, wet, no air moving, that's exactly the kind of environment where bacteria like Salmonella and Clostridium thrive. Constant airflow reduces the conditions where that happens. I'm not going to tell you the Grubhouse is sterile, it's a bin full of decomposing food and thousands of larvae. But it's a fundamentally different environment than a tub that's been sitting in its own moisture for a week, and that's a better meal going into your animals.
Who it's for, and who it isn't
If you want to try a DIY bin and see if this is for you, I'd point you at the BSFL Bin Kit first. It's the printed parts, the entrance pod, egg tree, and ramp, for a tote you already own. It's cheap, it works, and if you like building things, build it.
The Grubhouse is for people who've decided they want a system for producing healthy feed and would rather not build one. I honestly think that includes a lot of beginners. When something goes wrong in a homemade tub you're troubleshooting the bin and the biology at the same time, and you usually can't tell which one broke. Take the airflow problem, the harvest problem, and the egg-access problem off the table and what's left is just the animals.
It doesn't make you good at raising BSFL, though. You still have to learn what to feed them and how much, what a healthy bin looks like versus one that's about to go bad. That takes a season. Which is why every Grubhouse ships with The First Season, a short lesson from me every few days starting the day you order, so by the time the unit shows up you've done the homework.
The practical stuff
- $350, built to order, full payment at order. Lead time is 3 to 6 weeks because I build each one by hand.
- Shipping is $75 flat in the lower 48, one box. Along Colorado's Front Range, Fort Collins to Colorado Springs, delivery and setup are free and I'll bring it out myself.
- It goes in the shade. Always. Sunny bins cook colonies, and the sun isn't kind to the unit either.
- The lid fins let the smell out, and if there are wild black soldier flies where you live, that's what gets their attention. I can't promise they'll show up. Plenty of people start with a purchased batch of larvae instead.
If you've got a question I didn't answer here, email me. The product page is here.
