They spawn a lot faster on rotten turnips only took 3 mins after dropping rotten turnips.

Caught a single can placed by stream for 1.5 days. Time caught: morning.

 Click to Enlarge

I have had like 10 garbage items outside for more than a week and I've seen one (1) fly, that I accidentally scared away

I left a can by the ocean and by a pond. Both spawned a fly. But if I missed I had to wait ar least 24hrs before respawn.

I can confirm that a fly can spawn on a spoiled turnip. I left out a turnip for ants, but a fly spawned on it

This game feeds on spoiling our plans... I swear...

i left out a spoiled turnip and only ants spawn on it.

I left out a boot and it spawned once but I accidentally scared it away and that was 3 hours ago and it still hasn't spawned back

keep at least 1 turnip after 1 week for spoiled turnip

How do you get rotten fruit?

Found on rotting fruit and garbage.