Grub Enthusiast - "When I said boring plastic buckets earlier, I did not mean yours. I have built a couple of failed BSF harvester prototypes. I was starting by cutting two cat litter buckets..."

I knew you weren't directly criticizing my bucket design, but seeing the words "boring" and "plastic bucket" in the same sentence gave me a rash. It's better now. smile I also started with a square cat litter bucket which you can see in earlier posts here.

It might be possible for me to ID a medium size BSF larva if I had a good photo. The weather in northern California does seem too cool at this time to support BSF reproduction, but I can't be sure about that. Just looking at weather stats I would guess that Seattle never has proper BSF weather yet there they are. The best way to check your larvae is to keep one in a jar until it pupates. I think most of the common pest species mature quickly so you might get an adult in a few weeks. There are other fly larvae that are similar in size to BSF. Once I found large larvae that could easily be mistaken for BSF and I collected one. When the adult emerged I had a False Stable Fly. Blowfly maggots also get as large as BSF. If you can upload a photo of your larvae I'll try to ID it. A close up of a few larvae would be best.

You can literally use any container as the basis for a BSF unit. To get the most functionality you need to incorporate; a way to let the mature larvae out, drainage, ventilation, and a way to stop the larvae from exiting in an uncontrolled fashion. Good drainage and ventilation are the only ones I consider mandatory. One consideration if you bury something in the ground is ants and other critters. So far I haven't had a big problem with ants but under some circumstances they will attack BSF.