Glad I read the posts on this thread! Worms have been an issue for me also lately, different ones I'm not sure which is which. The large green guys (cabbage worms?), webworms, and a black cp with a stripe down it's back that I have no idea what is....lots of those on calendula seedlings this late spring, a few now. I've also found green inchworms on my new roman chamomile, well underneath. I would've never seen them if I hadn't gone after the slug on the plants. Being an "organic" gardener, this means I hand pick and squish these guys usually....but it's so bad I was wondering about bt. Now that I see it's only effective if they are young...what do I do? Time to spend handpicking is limited now, and the green guys are hard to spot....even with all the poop. Any suggestions? I never see the eggs....only the worms. Can bt be used as a preventative measure?

You had great sucess the first time. I would do the same exact thing that you had great success with the first time 3 to 6 more times. Each year you will have 2 MORE inches deep, rich soil in your great "location, location, location," for some lucky plants. Your garden is two inches closer to heaven than everybody else. Two inches of great soil right where you want it is two inches more then others who did not bother last year to follow your method have to start their garden in this year. Eventually, even if you stop gardening for 10 years, this part of the garden will always be a bit higher and a bit greener than all the rest. Sort of in memory of all your hard work on it's behalf.

A few of them are going to escape and die. When you are really new to this you may agonise over every worm ( I hope you aren't giving them names : -) I'm not sure why they do some suicidal things but they do. All you can hope is that they are breeding faster than they are commiting suicide. I find crispy worms that escaped all the time. As long as you are finding lots of tiny baby worms I wouldn't worry about a couple that got away.

With regard to the heat, yes it will be a big problem. I deal with it here in Florida by partially filling plastic soft drink or water bottles with water and freezing them. I then place the bottles, wrapped in newspaper, in the worm bins. From the way they migrate close to the bottle, they appear to love it.