Setup Guides: The Grubhouse and BSFL Bin Kit

The Grubhouse Setup Guide

No tools needed. Plan on about 20 minutes. Set it up where it is going to live. A loaded Grubhouse is not something you want to move.

Before you open the box

Everything ships in one box. Lay it all out and check it against this list:

Top and walls (one assembled piece, hatch installed)
Grub Track ring
2 tubs
2 exit ramps
2 deflector pieces
2 egg trap bases and 8 magnet leaves
Hatch-rest dowel
Wire frame kit: 4 posts, 2 shelves, 8 split sleeves

Not in the box, and you will want it on setup day: a block of coco coir (we sell coir bricks here at bluegrubfarm.com), and a couple of bricks or a paver if the unit is going outdoors.

Step 1 — Assemble the wire frame

Find the mark on each post. Each post has a lower mark and an upper mark. The posts are grooved all the way up; the marks tell you which groove the shelves lock into.
Snap a split sleeve onto each post at the lower mark. The sleeve is two halves. Close them around the post so the lip inside drops into the groove at the mark. You will feel it seat. Do all four posts.
Push each post up through a corner collar of the bottom shelf. Lay the shelf on its side if that is easier. The post slides until the collar hits the sleeve and stops.
Stand the frame up and press the bottom shelf down firmly at all four corners. It locks onto the sleeves. If a corner rocks, push that corner down again.
Snap the second set of sleeves onto the posts at the upper mark.
Lower the upper shelf down over the four posts until it lands on the sleeves.
Press the upper shelf down at every corner until it locks. Give the whole frame a wiggle. Solid means done. Optional: a dab of super glue on each sleeve helps the frame stay together if you ever move the Grubhouse.

Step 2 — Slide on the Grub Track

The Grub Track is one ring with a hole in each corner. Line the corner holes up with the four posts and lower the ring straight down. It rides the posts and comes to rest on the upper shelf. The side with the opening in the outer rail is the front of the unit.

Step 3 — Clip on the deflector pieces

The opening in the front rail is where your grubs will drop through to the collection tub. The two black deflector pieces hook over the front rail, one on each side of that opening. They hang down beneath the rail and guide whatever drops into the tub below. Hook each one on and press it down until it sits flat.

Step 4 — Place the tubs

Bottom tub on the bottom shelf. This is the collection tub. Your harvest lands here.
Top tub on the upper shelf, inside the Grub Track ring. This is the colony tub, where the larvae live and eat.

If you would rather put the top on first and slide the tubs in afterward, that works too. Either order is fine.

Step 5 — Set the top and walls on

The top and the walls come as one built piece: the roof, the entrance fins, the feeding hatch, and the shade cloth walls, already attached.

Lift the assembly up and over the frame with the cloth hanging down around the outside. Hold it by the rigid top, not the cloth.
Open the door flap so you can see the corners.
Seat the four corner caps onto the tops of the four posts. Get all four started before pushing any of them fully home.
Press down at each corner until the top sits flat. You will feel it drop onto the posts. Check all four corners again.
Close the door flap and hook the dongle over the knob. That is what holds it shut. Open and close it a couple of times to get the feel of it.

Step 6 — Clip the bottom edge of the walls

Work your way around the base of the unit and clip the bottom edge of the cloth to the bottom shelf. Pull the cloth snug as you go, not tight, just no slack. Take your time at the corners. This keeps the walls from flapping and keeps things from getting in underneath.

Step 7 — Egg traps and exit ramps

Egg traps. You have two black bases and eight green magnet leaves.

Reach in through the door flap and set a base on the rim of the colony tub, one on each side. Press each one down so it sits flat and does not rock. Nothing to tighten.
Open the feeding hatch. From above, snap four leaves onto each base. They are magnetic and click straight on.
Later, to check for eggs, pull a leaf off, look, and snap it back on. About fifteen seconds, no digging.

Exit ramps. Hook each ramp over the rim of the colony tub with the long end resting down inside the tub, one on each long side. When larvae finish growing they climb the ramp, go over the lip, and drop onto the Grub Track below. The track carries them around to the front opening and they fall into the collection tub. That is your harvest, and it collects itself.

Before you add any grubs

1. Coir in the collection tub. Put one to two inches of loose coco coir in the bottom tub. It is a soft landing bed for the harvest. Coir goes in the bottom tub only, not the colony tub.

2. Ballast, if it lives outdoors. Put a couple of bricks or a paver in the bottom tub alongside the coir. The Grubhouse is tall and wrapped in cloth, and wind catches cloth. If it is in a garage, shed, or outbuilding, skip this.

3. Shade. Always. The Grubhouse goes in full shade, all day. Under a tree, the north side of a building, a fence line that never gets direct light. Morning-only shade does not count. If sun reaches the spot at any hour, move it now while it is still easy. A sunny bin gets hot fast, and a cooked colony does not come back.

Quick checks

Frame does not rock when you push on it.
Track ring is sitting flat on the upper shelf, front opening facing the way you want to walk up to it.
Both deflector pieces are hooked over the front rail and pressed down.
Top sits flat on all four posts; door flap closes with the dongle hooked over the knob.
Cloth is clipped to the bottom shelf all the way around with no sagging.
Four leaves on each egg trap base; two ramps hooked over the colony tub rim.
Coir in the bottom tub. Ballast if outdoors. Full shade.

Stuck on anything? Email grubbear@bluegrubfarm.com. You will get an answer, and so will the next version of these instructions.

Bin Kit Setup Guide

How to set up the Bin Kit for your BSFL.

What's Included

Everything you need to turn any plastic storage tote into a self-harvesting BSF composter. The bin itself is not included — you'll provide your own.

Note: Bin not included. This kit works with any plastic storage tote you already own. Any size tote with a solid lid works. I wouldn't go under 12 gallons, and if you go bigger than about 27 gallons you may want two kits. The taller the walls, the better — more vertical distance means a better-performing harvest ramp.

Black Soldier Fly Entrance — 3D-printed, brown. Mounts in the lid for adult BSF entry.
BSF Entrance Base Ring — Secures the entrance from inside the lid.
Branch Segments — 3D-printed, brown. Snap together to form the lure frame.
Leaf Lures — 3D-printed, green. Friction-fit onto branch tips.
Self-Harvest Ramp — 3D-printed, black. Guides prepupae out automatically.
Ramp Brackets — Friction-fit to the tote wall.
Harvest Pouch — Small cloth bag. Slips over ramp exit to collect prepupae.

Tools You'll Need

Soldering iron or wood-burning tool (we recommend the WORX MakerX, set to ~400°F) — used to melt openings in the plastic tote
Flat, heat-safe work surface
Protective gloves — optional but recommended when cutting plastic

Setup Instructions

Step 1 — Prepare Your Bin

You'll need any plastic storage tote with a lid — any size works, I wouldn't go under 12 gallons, and past about 27 gallons you may want two kits. Using the soldering iron or wood-burning tool heated to approximately 400°F, carefully melt a rectangular ventilation opening (roughly 3″ × 1.5″) on the upper side wall of the tote, near a corner. This vent allows airflow and is the exit point for your self-harvesting prepupae.

Step 2 — Install the Self-Harvest Ramp

Attach the two ramp brackets to the inside wall of the tote, directly below the vent opening. Press them firmly — they grip via friction fit. Slide the self-harvest ramp into the brackets so it angles toward the vent. Mature prepupae will crawl up and out on their own. Slip the included cloth harvest pouch over the outside end of the ramp — prepupae fall directly into it, keeping your harvest clean and contained.

Step 3 — Cut the Entrance Hole in the Lid

Flip the lid upside down on your work surface. Trace the base of the BSF Entrance onto the lid to mark your cut circle, then use the soldering iron to melt along that line. Work slowly — the hole should be just wide enough for the entrance to drop through snugly without wiggling.

Step 4 — Install the BSF Entrance

From the top side of the lid, drop the Black Soldier Fly Entrance into the hole you just cut. Flip the lid over and thread the base ring onto the entrance from below, twisting until snug. The base ring locks it in place and gives adult BSF flies access to enter and lay eggs inside.

Step 5 — Assemble the Leaf Lure

Snap the four branch segments together to form the lure frame. Press each of the 12 green leaf pieces onto the branch tips — they friction-fit into place. Attach the completed leaf assembly to the underside of the lid via the BSF Entrance base ring. The leaves hang down inside the bin and attract adult BSF flies up toward the entrance above.

Step 6 — Add Your Starter Larvae

Place a layer of food scraps (fruit, vegetables, grains, or coffee grounds) in the bottom of the tote, about 2–3 inches deep. Add your starter larvae on top of the food. Close the lid, place the bin in a shaded outdoor spot, and you're done.

Safety Note

Always use caution when operating a soldering iron or wood-burning tool. Work in a well-ventilated area when melting plastic. Keep tools away from children. Never leave a hot iron unattended.

Tips for Best Results

Location Matters

Place your bin in a shaded area with some indirect sunlight. BSF adults need warmth and light to find the bin and lay eggs.

Feed Gradually

Start with soft, moist food scraps. Avoid large bones, dairy, and excessive oils until your colony is well established.

Harvest Regularly

Check the harvest pouch daily. Prepupae that crawl out make excellent feed for chickens, reptiles, fish, and wild birds.

Use the Frass

The frass (castings) left behind is a powerful organic fertilizer. Harvest every few weeks and add directly to your garden.

Still Have Questions?

Our team is happy to help with setup questions, colony troubleshooting, or feedback on your Bin Kit experience.

Email Support | Read the BSFL Guide

Set up your Grubhouse or Bin Kit.