Now that you have removed the WOW they should be fine. Using the WOWs created a nice warm and damp incubator for the soil fungi to grow but now that there is adequate air circulation and the soil can dry out some it will die off.

I'm surprised that you'd ever have to use WOWs in your zone this far into spring? If you do use them be sure to leave the tops open and remove them ASAP. And keep in mind that soil in containers warms up much faster than in-ground soil does and it drains much faster too. So unless there was risk of killer frost the WOWs aren't really needed.

Dave

Thanks Dave, I was hoping it was a benign fungus from being moist and contained. We've had a bad spring this year. Night temps are finally just scraping by over 50. It's been the coldest and wettest spring in a very very long time. I actually had removed the WOWs a few weeks ago when I thought it was warming up. We got hit with a series of really bad storms....high winds, driving rain and hail. I covered them back up for protection. My cherry tomato plants have some weather damage (since they were bigger and poking up above the WOWs). My heirlooms look good expect for being a little squished in the WOW. We have more rain in the forecast but at least temps at night are consistently 50. I uncovered them so hopefully they'll do well. Thanks for the advice!