Were to raise seeds (herbs and stuff)

I usually raise my seedlings in these white boxes you get from the greengrocer on the terrace. That is OK as long as these are vegetable seedlings.
But herbs which often need longer time to germinate and/or are very fine seeds don't do very well there, it is just too hot and sunny. I have to water several times a day - on hour too late and everything is bone dry.
I have a nice area under a decidious tree, but when I put the boxes on the ground I will almost certainly have slugs eating my seedlings.
A table is OK as long as it is dry and there are not so many slugs, but as soon as it is wet they climb, and then they are sitting under the pots or boxes.
What do you use to propagate herb seedlings? Do nursery benches make a difference? Do you think it is a good idea to raise seedligs under a tree?
Or is it better having beds for raising seedlings?

One thing I've done for ants on plant benches in a greenhouse (in addition to my dining table, and my bed---lots of ants !!) which might work for slugs too is to put the legs of the bench or table in cans or other containers of oil or soapy water, which forms a moat most small critters won't cross, and drowns them if they try.

That is an idea! Actually I plan to use a table at least for some of the stuff.