How big are your bins? Are they in contact with the ground? If the bins are not in contact with the ground, then the worms are a captive and cannot get away from the heat. The temps you mentioned will kill the worms if they cannot leave. Are you pocket feeding?

My bins are large rubbermaid bins. Most of the areas in the bins are

Funny, I just checked one of my pockets and it seemed a little warm, but with plenty of nematodes.

Worms a plenty in the next pocket, and don't forget the far corner with Watermelon rinds.

Man I do know how I'm going to migrate them to the next bin (OSCR JR), watermelons all around :-)

I have many tote type bins and do not pocket feed because to much of the food I would bury would heat the bin up too much and the worms could not get away from the heat. I do pocket feed my outdoor bins sometimes,(especially in the winter..makes a makeshift furnace), but they are in contact with the ground and the worms can move out until things cool off. I think 90 is too hot. Have you tried top feeding your indoor bin? I do not worry about heating up as much and there is more surface area for the worms to feed.

I've noticed heat build up in the pockets when I fed that way too, especially with any kind of grain based matl.

I feed on top now (thin layers) and cover with shredded paper. I still have a slight heat increase, maybe 5 degrees, but they don't seem to mind 85 deg. and I rarely see the bin get above that.

bruce