So just as an experiment, I put some red wigglers and European night crawlers into a 4'x8' raised bed full of organic waste last fall to which I continued to add kitchen waste regularly since then, just to see what would happen. They have thrived and the bed is teeming with them now, and I'm hoping to keep things going. We have relatively hot summers here, consistently 100 degrees and up during high summer, and I have been covering the bed with a tarp, dark side up during the cold weather and light side up during the warm weather. I'd like to ditch the tarp and plant a few things in the bed, but still provide the worms with enough protection and insulation from the summer heat. Anyone have any suggestions? The beds have about 12-14 inches of rich organic matter so they have plenty of room to dig down. Do you think a good thick layer of straw mulch, like 3-4", would suffice if I kept it adequately moist?

By the way, I know this isn't the ideal way to raise worms, but again, this was just an experiment in the hopes of keeping my raised beds as full of rich OM as possible.